diff --git a/lib/hydra/pcdm.rb b/lib/hydra/pcdm.rb
index 3205c96c..51fce364 100644
--- a/lib/hydra/pcdm.rb
+++ b/lib/hydra/pcdm.rb
@@ -24,6 +24,9 @@ module PCDM
     autoload :GetCollectionsFromCollection,      'hydra/pcdm/services/collection/get_collections'
     autoload :GetObjectsFromCollection,          'hydra/pcdm/services/collection/get_objects'
     autoload :GetRelatedObjectsFromCollection,   'hydra/pcdm/services/collection/get_related_objects'
+    autoload :RemoveCollectionFromCollection,    'hydra/pcdm/services/collection/remove_collection'
+    autoload :RemoveObjectFromCollection,        'hydra/pcdm/services/collection/remove_object'
+    autoload :RemoveRelatedObjectFromCollection, 'hydra/pcdm/services/collection/remove_related_object'
 
     # object services
     autoload :AddFileToObject,                   'hydra/pcdm/services/object/add_file'
@@ -33,6 +36,8 @@ module PCDM
     autoload :GetObjectsFromObject,              'hydra/pcdm/services/object/get_objects'
     autoload :GetRelatedObjectsFromObject,       'hydra/pcdm/services/object/get_related_objects'
     autoload :GetFilesFromObject,                'hydra/pcdm/services/object/get_collections'
+    autoload :RemoveObjectFromObject,            'hydra/pcdm/services/object/remove_object'
+    autoload :RemoveRelatedObjectFromObject,     'hydra/pcdm/services/object/remove_related_object'
 
 
     # model validations
diff --git a/lib/hydra/pcdm/services/collection/get_related_objects.rb b/lib/hydra/pcdm/services/collection/get_related_objects.rb
index 4c88dea8..ad472793 100644
--- a/lib/hydra/pcdm/services/collection/get_related_objects.rb
+++ b/lib/hydra/pcdm/services/collection/get_related_objects.rb
@@ -10,8 +10,7 @@ class GetRelatedObjectsFromCollection
 
     def self.call( parent_collection )
       raise ArgumentError, "parent_collection must be a pcdm collection" unless Hydra::PCDM.collection? parent_collection
-
-      parent_collection.related_objects
+      parent_collection.related_objects.to_a
     end
 
   end
diff --git a/lib/hydra/pcdm/services/collection/remove_collection.rb b/lib/hydra/pcdm/services/collection/remove_collection.rb
new file mode 100644
index 00000000..344bc1ea
--- /dev/null
+++ b/lib/hydra/pcdm/services/collection/remove_collection.rb
@@ -0,0 +1,33 @@
+module Hydra::PCDM
+  class RemoveCollectionFromCollection
+
+    ##
+    # Remove a collection from a collection.
+    #
+    # @param [Hydra::PCDM::Collection] :parent_collection from which to remove collection
+    # @param [Hydra::PCDM::Collection] :child_collection being removed
+    #
+    # @return [Hydra::PCDM::Collection] the updated pcdm collection
+
+    def self.call( parent_collection, child_collection )
+      raise ArgumentError, "parent_collection must be a pcdm collection" unless Hydra::PCDM.collection? parent_collection
+      raise ArgumentError, "child_collection must be a pcdm collection" unless Hydra::PCDM.collection? child_collection
+
+
+      # TODO FIX when members is empty, members.delete raises ActiveFedora::ObjectNotFoundError "Can't reload an object that hasn't been saved"  (activefedora-aggregation issue #35)
+
+      # TODO members.delete should...   (issue #103)(activefedora-aggregation issue #34)
+      #   * return child_collection when successful delete
+      #   * return nil if child_collection does not exist in parent_collection
+      #   * raise error for any other problems
+
+      # parent_collection.members.delete child_collection                                # TODO Uncomment
+
+      return nil unless Hydra::PCDM::GetCollectionsFromCollection.call( parent_collection ).include? child_collection # TODO Remove
+      removed_collection = parent_collection.members.delete child_collection             # TODO Remove
+      removed_collection = removed_collection.first  if removed_collection.is_a? Array   # TODO Remove
+      removed_collection                                                                 # TODO Remove
+    end
+
+  end
+end
diff --git a/lib/hydra/pcdm/services/collection/remove_object.rb b/lib/hydra/pcdm/services/collection/remove_object.rb
new file mode 100644
index 00000000..c64dc9b5
--- /dev/null
+++ b/lib/hydra/pcdm/services/collection/remove_object.rb
@@ -0,0 +1,40 @@
+module Hydra::PCDM
+  class RemoveObjectFromCollection
+
+    ##
+    # Remove an object from a collection.
+    #
+    # @param [Hydra::PCDM::Collection] :parent_collection from which to remove object
+    # @param [Hydra::PCDM::Object] :child_object being removed
+    # @param [Fixnum] :nth_occurrence remove nth occurrence of this object in the list (default=1)
+    #
+    # @return [Hydra::PCDM::Collection] the updated pcdm collection
+
+    def self.call( parent_collection, child_object, nth_occurrence=1 )
+      raise ArgumentError, "parent_collection must be a pcdm collection" unless Hydra::PCDM.collection? parent_collection
+      raise ArgumentError, "child_object must be a pcdm object" unless Hydra::PCDM.object? child_object
+
+
+      # TODO FIX when members is empty, members.delete raises ActiveFedora::ObjectNotFoundError "Can't reload an object that hasn't been saved"  (activefedora-aggregation issue #35)
+
+      # TODO members.delete should...   (issue #103)(activefedora-aggregation issue #34)
+      #   * return child_object when successful delete
+      #   * return nil if child_object does not exist in parent_collection
+      #   * raise error for any other problems
+
+      # parent_collection.members.delete child_object                        # TODO Uncomment
+
+      return nil    unless parent_collection.members.include? child_object   # TODO Remove
+      removed_object = parent_collection.members.delete child_object         # TODO Remove
+      removed_object = removed_object.first  if removed_object.is_a? Array   # TODO Remove
+      removed_object                                                         # TODO Remove
+
+
+      # TODO -- The same object may be in the list multiple times.  (issue #102)
+      #   * How to remove nth occurrence?
+      #   * Default to removing 1st occurrence from the beginning of the list.
+
+    end
+
+  end
+end
diff --git a/lib/hydra/pcdm/services/collection/remove_related_object.rb b/lib/hydra/pcdm/services/collection/remove_related_object.rb
new file mode 100644
index 00000000..1867d4b5
--- /dev/null
+++ b/lib/hydra/pcdm/services/collection/remove_related_object.rb
@@ -0,0 +1,33 @@
+module Hydra::PCDM
+  class RemoveRelatedObjectFromCollection
+
+    ##
+    # Remove an object from a collection.
+    #
+    # @param [Hydra::PCDM::Collection] :parent_collection from which to remove the related object
+    # @param [Hydra::PCDM::Object] :child_related_object being removed
+    #
+    # @return [Hydra::PCDM::Collection] the updated pcdm collection
+
+    def self.call( parent_collection, child_related_object )
+      raise ArgumentError, "parent_collection must be a pcdm collection" unless Hydra::PCDM.collection? parent_collection
+      raise ArgumentError, "child_related_object must be a pcdm object" unless Hydra::PCDM.object? child_related_object
+
+
+      # TODO FIX when related_objects is empty, related_objects.delete raises ActiveFedora::ObjectNotFoundError "Can't reload an object that hasn't been saved"  (activefedora-aggregation issue #35)
+
+      # TODO members.delete should...   (issue #103)(activefedora-aggregation issue #34)
+      #   * return child_collection when successful delete
+      #   * return nil if child_collection does not exist in parent_collection
+      #   * raise error for any other problems
+
+      # parent_collection.related_objects.delete child_related_object                                # TODO Uncomment
+
+      return nil unless Hydra::PCDM::GetRelatedObjectsFromCollection.call( parent_collection ).include? child_related_object # TODO Remove
+      removed_related_object = parent_collection.related_objects.delete child_related_object         # TODO Remove
+      removed_related_object = removed_related_object.first  if removed_related_object.is_a? Array   # TODO Remove
+      removed_related_object                                                                         # TODO Remove
+    end
+
+  end
+end
diff --git a/lib/hydra/pcdm/services/object/get_related_objects.rb b/lib/hydra/pcdm/services/object/get_related_objects.rb
index 7c2c2806..13d940c1 100644
--- a/lib/hydra/pcdm/services/object/get_related_objects.rb
+++ b/lib/hydra/pcdm/services/object/get_related_objects.rb
@@ -10,8 +10,7 @@ class GetRelatedObjectsFromObject
 
     def self.call( parent_object )
       raise ArgumentError, "parent_object must be a pcdm object" unless Hydra::PCDM.object? parent_object
-
-      parent_object.related_objects
+      parent_object.related_objects.to_a
     end
 
   end
diff --git a/lib/hydra/pcdm/services/object/remove_object.rb b/lib/hydra/pcdm/services/object/remove_object.rb
new file mode 100644
index 00000000..63d2af53
--- /dev/null
+++ b/lib/hydra/pcdm/services/object/remove_object.rb
@@ -0,0 +1,40 @@
+module Hydra::PCDM
+  class RemoveObjectFromObject
+
+    ##
+    # Remove an object from an object.
+    #
+    # @param [Hydra::PCDM::Object] :parent_object from which to remove object
+    # @param [Hydra::PCDM::Object] :child_object being removed
+    # @param [Fixnum] :nth_occurrence remove nth occurrence of this object in the list (default=1)
+    #
+    # @return [Hydra::PCDM::Object] the updated pcdm object
+
+    def self.call( parent_object, child_object, nth_occurrence=1 )
+      raise ArgumentError, "parent_object must be a pcdm object" unless Hydra::PCDM.object? parent_object
+      raise ArgumentError, "child_object must be a pcdm object" unless Hydra::PCDM.object? child_object
+
+
+      # TODO FIX when members is empty, members.delete raises ActiveFedora::ObjectNotFoundError "Can't reload an object that hasn't been saved"  (activefedora-aggregation issue #35)
+
+      # TODO members.delete should...   (issue #103)(activefedora-aggregation issue #34)
+      #   * return child_object when successful delete
+      #   * return nil if child_object does not exist in parent_object
+      #   * raise error for any other problems
+
+      # parent_object.members.delete child_object                            # TODO Uncomment
+
+      return nil    unless parent_object.members.include? child_object       # TODO Remove
+      removed_object = parent_object.members.delete child_object             # TODO Remove
+      removed_object = removed_object.first  if removed_object.is_a? Array   # TODO Remove
+      removed_object                                                         # TODO Remove
+
+
+      # TODO -- The same object may be in the list multiple times.  (issue #102)
+      #   * How to remove nth occurrence?
+      #   * Default to removing 1st occurrence from the beginning of the list.
+
+    end
+
+  end
+end
diff --git a/lib/hydra/pcdm/services/object/remove_related_object.rb b/lib/hydra/pcdm/services/object/remove_related_object.rb
new file mode 100644
index 00000000..3a57988e
--- /dev/null
+++ b/lib/hydra/pcdm/services/object/remove_related_object.rb
@@ -0,0 +1,33 @@
+module Hydra::PCDM
+  class RemoveRelatedObjectFromObject
+
+    ##
+    # Remove an object from an object.
+    #
+    # @param [Hydra::PCDM::Object] :parent_object from which to remove the related object
+    # @param [Hydra::PCDM::Object] :child_related_object being removed
+    #
+    # @return [Hydra::PCDM::Collection] the updated pcdm collection
+
+    def self.call( parent_object, child_related_object )
+      raise ArgumentError, "parent_object must be a pcdm object" unless Hydra::PCDM.object? parent_object
+      raise ArgumentError, "child_related_object must be a pcdm object" unless Hydra::PCDM.object? child_related_object
+
+
+      # TODO FIX when related_objects is empty, related_objects.delete raises ActiveFedora::ObjectNotFoundError "Can't reload an object that hasn't been saved"  (activefedora-aggregation issue #35)
+
+      # TODO members.delete should...   (issue #103)(activefedora-aggregation issue #34)
+      #   * return child_related_object when successful delete
+      #   * return nil if child_related_object does not exist in parent_object
+      #   * raise error for any other problems
+
+      # parent_object.related_objects.delete child_related_object                                    # TODO Uncomment
+
+      return nil unless Hydra::PCDM::GetRelatedObjectsFromObject.call( parent_object ).include? child_related_object # TODO Remove
+      removed_related_object = parent_object.related_objects.delete child_related_object             # TODO Remove
+      removed_related_object = removed_related_object.first  if removed_related_object.is_a? Array   # TODO Remove
+      removed_related_object                                                                         # TODO Remove
+    end
+
+  end
+end
diff --git a/spec/hydra/pcdm/services/collection/add_collection_spec.rb b/spec/hydra/pcdm/services/collection/add_collection_spec.rb
index 94f9f37c..e9e8f887 100644
--- a/spec/hydra/pcdm/services/collection/add_collection_spec.rb
+++ b/spec/hydra/pcdm/services/collection/add_collection_spec.rb
@@ -31,13 +31,14 @@
         expect( Hydra::PCDM::GetCollectionsFromCollection.call( collection1 ) ).to eq [collection2]
       end
 
-      xit 'should allow collections to repeat' do
-        # TODO Can collections repeat???
+      it 'should allow collections to repeat' do
+        skip 'skipping this test because issue #94 needs to be addressed' do
         Hydra::PCDM::AddCollectionToCollection.call( subject, collection1 )
         Hydra::PCDM::AddCollectionToCollection.call( subject, collection2 )
         Hydra::PCDM::AddCollectionToCollection.call( subject, collection1 )
         expect( Hydra::PCDM::GetCollectionsFromCollection.call( subject ) ).to eq [collection1,collection2,collection1]
       end
+      end
 
       context 'with collections and objects' do
         before do
diff --git a/spec/hydra/pcdm/services/collection/add_related_object_spec.rb b/spec/hydra/pcdm/services/collection/add_related_object_spec.rb
index 8293af02..052b661c 100644
--- a/spec/hydra/pcdm/services/collection/add_related_object_spec.rb
+++ b/spec/hydra/pcdm/services/collection/add_related_object_spec.rb
@@ -85,7 +85,8 @@
       let(:object1) { Hydra::PCDM::Object.create }
       let(:object2) { Hydra::PCDM::Object.create }
 
-      xit 'should NOT allow related objects to repeat' do
+      it 'should NOT allow related objects to repeat' do
+        skip 'skipping this test because issue #92 needs to be addressed' do
         Hydra::PCDM::AddRelatedObjectToCollection.call( subject, object1 )
         Hydra::PCDM::AddRelatedObjectToCollection.call( subject, object2 )
         Hydra::PCDM::AddRelatedObjectToCollection.call( subject, object1 )
@@ -94,6 +95,7 @@
         expect( related_objects.include? object2 ).to be true
         expect( related_objects.size ).to eq 2
       end
+      end
     end
   end
 end
diff --git a/spec/hydra/pcdm/services/collection/remove_collection_spec.rb b/spec/hydra/pcdm/services/collection/remove_collection_spec.rb
new file mode 100644
index 00000000..f49a7f13
--- /dev/null
+++ b/spec/hydra/pcdm/services/collection/remove_collection_spec.rb
@@ -0,0 +1,143 @@
+require 'spec_helper'
+
+describe Hydra::PCDM::RemoveCollectionFromCollection do
+
+  subject { Hydra::PCDM::Collection.create }
+
+    let(:collection1) { Hydra::PCDM::Collection.create }
+    let(:collection2) { Hydra::PCDM::Collection.create }
+    let(:collection3) { Hydra::PCDM::Collection.create }
+    let(:collection4) { Hydra::PCDM::Collection.create }
+    let(:collection5) { Hydra::PCDM::Collection.create }
+
+    let(:object1) { Hydra::PCDM::Object.create }
+    let(:object2) { Hydra::PCDM::Object.create }
+
+
+  describe '#call' do
+    context 'when it is the only collection' do
+
+      before do
+        Hydra::PCDM::AddCollectionToCollection.call( subject, collection1 )
+        subject.save
+        expect( Hydra::PCDM::GetCollectionsFromCollection.call( subject.reload )).to eq [collection1]
+      end
+
+      it 'should remove collection' do
+        expect( Hydra::PCDM::RemoveCollectionFromCollection.call( subject, collection1 ) ).to eq collection1
+        expect( Hydra::PCDM::GetCollectionsFromCollection.call( subject.reload )).to eq []
+      end
+
+      it 'should remove collection only when objects' do
+        Hydra::PCDM::AddObjectToCollection.call( subject, object1 )
+        Hydra::PCDM::AddObjectToCollection.call( subject, object2 )
+        expect( Hydra::PCDM::RemoveCollectionFromCollection.call( subject, collection1 ) ).to eq collection1
+        expect( Hydra::PCDM::GetCollectionsFromCollection.call( subject.reload )).to eq []
+        expect( Hydra::PCDM::GetObjectsFromCollection.call( subject )).to eq [object1,object2]
+      end
+    end
+
+    context 'when multiple collections' do
+      before do
+        Hydra::PCDM::AddCollectionToCollection.call( subject, collection1 )
+        Hydra::PCDM::AddCollectionToCollection.call( subject, collection2 )
+        Hydra::PCDM::AddCollectionToCollection.call( subject, collection3 )
+        Hydra::PCDM::AddCollectionToCollection.call( subject, collection4 )
+        Hydra::PCDM::AddCollectionToCollection.call( subject, collection5 )
+        subject.save
+        expect( Hydra::PCDM::GetCollectionsFromCollection.call( subject.reload )).to eq [collection1,collection2,collection3,collection4,collection5]
+      end
+
+      it 'should remove first collection' do
+        expect( Hydra::PCDM::RemoveCollectionFromCollection.call( subject, collection1 ) ).to eq collection1
+        expect( Hydra::PCDM::GetCollectionsFromCollection.call( subject.reload )).to eq [collection2,collection3,collection4,collection5]
+      end
+
+      it 'should remove last collection' do
+        expect( Hydra::PCDM::RemoveCollectionFromCollection.call( subject, collection5 ) ).to eq collection5
+        expect( Hydra::PCDM::GetCollectionsFromCollection.call( subject.reload )).to eq [collection1,collection2,collection3,collection4]
+      end
+
+      it 'should remove middle collection' do
+        expect( Hydra::PCDM::RemoveCollectionFromCollection.call( subject, collection3 ) ).to eq collection3
+        expect( Hydra::PCDM::GetCollectionsFromCollection.call( subject.reload )).to eq [collection1,collection2,collection4,collection5]
+      end
+    end
+
+    context 'when collection is missing' do
+      it 'should return nil' do
+        subject.save
+        expect( Hydra::PCDM::RemoveCollectionFromCollection.call( subject.reload, collection1 ) ).to be nil
+      end
+
+      it 'should return nil' do
+        Hydra::PCDM::AddObjectToCollection.call( subject, object1 )
+        Hydra::PCDM::AddObjectToCollection.call( subject, object2 )
+        subject.save
+        expect( Hydra::PCDM::RemoveCollectionFromCollection.call( subject.reload, collection1 ) ).to be nil
+      end
+
+      it 'should return nil' do
+        Hydra::PCDM::AddCollectionToCollection.call( subject, collection1 )
+        Hydra::PCDM::AddCollectionToCollection.call( subject, collection2 )
+        Hydra::PCDM::AddCollectionToCollection.call( subject, collection4 )
+        Hydra::PCDM::AddCollectionToCollection.call( subject, collection5 )
+        subject.save
+        expect( Hydra::PCDM::RemoveCollectionFromCollection.call( subject.reload, collection3 ) ).to be nil
+      end
+    end
+  end
+
+  context 'with unacceptable collections' do
+    let(:object1)  { Hydra::PCDM::Object.create }
+    let(:file1)    { Hydra::PCDM::File.new }
+    let(:non_PCDM_object) { "I'm not a PCDM object" }
+    let(:af_base_object)  { ActiveFedora::Base.create }
+
+    let(:error_type)    { ArgumentError }
+    let(:error_message) { 'child_collection must be a pcdm collection' }
+
+    it 'should NOT remove Hydra::PCDM::Objects from collections aggregation' do
+      expect{ Hydra::PCDM::RemoveCollectionFromCollection.call( subject, object1 ) }.to raise_error(error_type,error_message)
+    end
+
+    it 'should NOT remove Hydra::PCDM::Files from collections aggregation' do
+      expect{ Hydra::PCDM::RemoveCollectionFromCollection.call( subject, file1 ) }.to raise_error(error_type,error_message)
+    end
+
+    it 'should NOT remove non-PCDM objects from collections aggregation' do
+      expect{ Hydra::PCDM::RemoveCollectionFromCollection.call( subject, non_PCDM_object ) }.to raise_error(error_type,error_message)
+    end
+
+    it 'should NOT remove AF::Base objects from collections aggregation' do
+      expect{ Hydra::PCDM::RemoveCollectionFromCollection.call( subject, af_base_object ) }.to raise_error(error_type,error_message)
+    end
+  end
+
+  context 'with unacceptable parent collection' do
+    let(:collection2)      { Hydra::PCDM::Collection.create }
+    let(:object1)          { Hydra::PCDM::Object.create }
+    let(:file1)            { Hydra::PCDM::File.new }
+    let(:non_PCDM_object)  { "I'm not a PCDM object" }
+    let(:af_base_object)   { ActiveFedora::Base.create }
+
+    let(:error_type)    { ArgumentError }
+    let(:error_message) { 'parent_collection must be a pcdm collection' }
+
+    it 'should NOT accept Hydra::PCDM::Objects as parent collection' do
+      expect{ Hydra::PCDM::RemoveCollectionFromCollection.call( object1, collection2 ) }.to raise_error(error_type,error_message)
+    end
+
+    it 'should NOT accept Hydra::PCDM::Files as parent collection' do
+      expect{ Hydra::PCDM::RemoveCollectionFromCollection.call( file1, collection2 ) }.to raise_error(error_type,error_message)
+    end
+
+    it 'should NOT accept non-PCDM objects as parent collection' do
+      expect{ Hydra::PCDM::RemoveCollectionFromCollection.call( non_PCDM_object, collection2 ) }.to raise_error(error_type,error_message)
+    end
+
+    it 'should NOT accept AF::Base objects as parent collection' do
+      expect{ Hydra::PCDM::RemoveCollectionFromCollection.call( af_base_object, collection2 ) }.to raise_error(error_type,error_message)
+    end
+  end
+end
diff --git a/spec/hydra/pcdm/services/collection/remove_object_spec.rb b/spec/hydra/pcdm/services/collection/remove_object_spec.rb
new file mode 100644
index 00000000..ac81d9c2
--- /dev/null
+++ b/spec/hydra/pcdm/services/collection/remove_object_spec.rb
@@ -0,0 +1,180 @@
+require 'spec_helper'
+
+describe Hydra::PCDM::RemoveObjectFromCollection do
+
+  subject { Hydra::PCDM::Collection.create }
+
+  let(:object1) { Hydra::PCDM::Object.create }
+  let(:object2) { Hydra::PCDM::Object.create }
+  let(:object3) { Hydra::PCDM::Object.create }
+  let(:object4) { Hydra::PCDM::Object.create }
+  let(:object5) { Hydra::PCDM::Object.create }
+
+  let(:collection1) { Hydra::PCDM::Collection.create }
+  let(:collection2) { Hydra::PCDM::Collection.create }
+
+  describe '#call' do
+    context 'when it is the only object' do
+      before do
+        Hydra::PCDM::AddObjectToCollection.call( subject, object1 )
+        subject.save
+        expect( Hydra::PCDM::GetObjectsFromCollection.call( subject.reload )).to eq [object1]
+      end
+
+      it 'should remove object' do
+        expect( Hydra::PCDM::RemoveObjectFromCollection.call( subject, object1 ) ).to eq object1
+        expect( Hydra::PCDM::GetObjectsFromCollection.call( subject.reload )).to eq []
+      end
+
+      it 'should remove object only when collections' do
+        Hydra::PCDM::AddCollectionToCollection.call( subject, collection1 )
+        Hydra::PCDM::AddCollectionToCollection.call( subject, collection2 )
+        expect( Hydra::PCDM::RemoveObjectFromCollection.call( subject, object1 ) ).to eq object1
+        expect( Hydra::PCDM::GetObjectsFromCollection.call( subject.reload )).to eq []
+        expect( Hydra::PCDM::GetCollectionsFromCollection.call( subject )).to eq [collection1,collection2]
+      end
+    end
+
+    context 'when multiple objects' do
+      before do
+        Hydra::PCDM::AddObjectToCollection.call( subject, object1 )
+        Hydra::PCDM::AddObjectToCollection.call( subject, object2 )
+        Hydra::PCDM::AddObjectToCollection.call( subject, object3 )
+        Hydra::PCDM::AddObjectToCollection.call( subject, object4 )
+        Hydra::PCDM::AddObjectToCollection.call( subject, object5 )
+        subject.save
+        expect( Hydra::PCDM::GetObjectsFromCollection.call( subject.reload )).to eq [object1,object2,object3,object4,object5]
+      end
+
+      it 'should remove first object' do
+        expect( Hydra::PCDM::RemoveObjectFromCollection.call( subject, object1 ) ).to eq object1
+        expect( Hydra::PCDM::GetObjectsFromCollection.call( subject.reload )).to eq [object2,object3,object4,object5]
+      end
+
+      it 'should remove last object' do
+        expect( Hydra::PCDM::RemoveObjectFromCollection.call( subject, object5 ) ).to eq object5
+        expect( Hydra::PCDM::GetObjectsFromCollection.call( subject.reload )).to eq [object1,object2,object3,object4]
+      end
+
+      it 'should remove middle object' do
+        expect( Hydra::PCDM::RemoveObjectFromCollection.call( subject, object3 ) ).to eq object3
+        expect( Hydra::PCDM::GetObjectsFromCollection.call( subject.reload )).to eq [object1,object2,object4,object5]
+      end
+    end
+
+    context 'when object repeats' do
+      before do
+        Hydra::PCDM::AddObjectToCollection.call( subject, object1 )
+        Hydra::PCDM::AddObjectToCollection.call( subject, object2 )
+        Hydra::PCDM::AddObjectToCollection.call( subject, object3 )
+        Hydra::PCDM::AddObjectToCollection.call( subject, object2 )
+        Hydra::PCDM::AddObjectToCollection.call( subject, object4 )
+        Hydra::PCDM::AddObjectToCollection.call( subject, object2 )
+        Hydra::PCDM::AddObjectToCollection.call( subject, object5 )
+        subject.save
+      end
+
+      # TODO pending implementation of multiple objects
+
+      it 'should remove first occurrence' do
+        skip 'skipping this test because issue #102 needs to be addressed' do
+        expect(Hydra::PCDM::GetObjectsFromCollection.call( subject.reload )).to eq [object1,object2,object3,object2,object4,object2,object5]
+        expect( Hydra::PCDM::RemoveObjectFromCollection.call( subject, object2 ) ).to eq object2
+        expect( Hydra::PCDM::GetObjectsFromCollection.call( subject.reload )).to eq [object1,object3,object2,object4,object2,object5]
+      end
+      end
+
+      it 'should remove last occurrence' do
+        skip 'skipping this test because issue #102 needs to be addressed' do
+        expect(Hydra::PCDM::GetObjectsFromCollection.call( subject.reload )).to eq [object1,object2,object3,object2,object4,object2,object5]
+        expect( Hydra::PCDM::RemoveObjectFromCollection.call( subject, object2, -1 ) ).to eq object2
+        expect( Hydra::PCDM::GetObjectsFromCollection.call( subject.reload )).to eq [object1,object2,object3,object2,object4,object5]
+      end
+      end
+
+      it 'should remove nth occurrence' do
+        skip 'skipping this test because issue #102 needs to be addressed' do
+        expect(Hydra::PCDM::GetObjectsFromCollection.call( subject.reload )).to eq [object1,object2,object3,object2,object4,object2,object5]
+        expect( Hydra::PCDM::RemoveObjectFromCollection.call( subject, object2, 2 ) ).to eq object2
+        expect( Hydra::PCDM::GetObjectsFromCollection.call( subject.reload )).to eq [object1,object2,object3,object4,object2,object5]
+      end
+      end
+    end
+
+    context 'when object is missing' do
+      it 'should return nil' do
+        subject.save
+        expect( Hydra::PCDM::RemoveObjectFromCollection.call( subject.reload, object1 )).to be nil
+      end
+
+      it 'should return nil' do
+        Hydra::PCDM::AddCollectionToCollection.call( subject, collection1 )
+        Hydra::PCDM::AddCollectionToCollection.call( subject, collection2 )
+        subject.save
+        expect( Hydra::PCDM::RemoveObjectFromCollection.call( subject.reload, object1 )).to be nil
+      end
+
+      it 'should return nil' do
+        Hydra::PCDM::AddObjectToCollection.call( subject, object1 )
+        Hydra::PCDM::AddObjectToCollection.call( subject, object2 )
+        Hydra::PCDM::AddObjectToCollection.call( subject, object4 )
+        Hydra::PCDM::AddObjectToCollection.call( subject, object5 )
+        subject.save
+        expect( Hydra::PCDM::RemoveObjectFromCollection.call( subject.reload, object3 )).to be nil
+      end
+    end
+  end
+
+  context 'with unacceptable objects' do
+    let(:collection1)      { Hydra::PCDM::Collection.create }
+    let(:file1)    { Hydra::PCDM::File.new }
+    let(:non_PCDM_object) { "I'm not a PCDM object" }
+    let(:af_base_object)  { ActiveFedora::Base.create }
+
+    let(:error_type)    { ArgumentError }
+    let(:error_message) { 'child_object must be a pcdm object' }
+
+    it 'should NOT remove Hydra::PCDM::Collections from objects aggregation' do
+      expect{ Hydra::PCDM::RemoveObjectFromCollection.call( subject, collection1 ) }.to raise_error(error_type,error_message)
+    end
+
+    it 'should NOT remove Hydra::PCDM::Files from objects aggregation' do
+      expect{ Hydra::PCDM::RemoveObjectFromCollection.call( subject, file1 ) }.to raise_error(error_type,error_message)
+    end
+
+    it 'should NOT remove non-PCDM objects from objects aggregation' do
+      expect{ Hydra::PCDM::RemoveObjectFromCollection.call( subject, non_PCDM_object ) }.to raise_error(error_type,error_message)
+    end
+
+    it 'should NOT remove AF::Base objects from objects aggregation' do
+      expect{ Hydra::PCDM::RemoveObjectFromCollection.call( subject, af_base_object ) }.to raise_error(error_type,error_message)
+    end
+  end
+
+  context 'with unacceptable parent collection' do
+    let(:collection2)      { Hydra::PCDM::Collection.create }
+    let(:object1)          { Hydra::PCDM::Object.create }
+    let(:file1)            { Hydra::PCDM::File.new }
+    let(:non_PCDM_object)  { "I'm not a PCDM object" }
+    let(:af_base_object)   { ActiveFedora::Base.create }
+
+    let(:error_type)    { ArgumentError }
+    let(:error_message) { 'parent_collection must be a pcdm collection' }
+
+    it 'should NOT accept Hydra::PCDM::Objects as parent collection' do
+      expect{ Hydra::PCDM::RemoveObjectFromCollection.call( object1, collection2 ) }.to raise_error(error_type,error_message)
+    end
+
+    it 'should NOT accept Hydra::PCDM::Files as parent collection' do
+      expect{ Hydra::PCDM::RemoveObjectFromCollection.call( file1, collection2 ) }.to raise_error(error_type,error_message)
+    end
+
+    it 'should NOT accept non-PCDM objects as parent collection' do
+      expect{ Hydra::PCDM::RemoveObjectFromCollection.call( non_PCDM_object, collection2 ) }.to raise_error(error_type,error_message)
+    end
+
+    it 'should NOT accept AF::Base objects as parent collection' do
+      expect{ Hydra::PCDM::RemoveObjectFromCollection.call( af_base_object, collection2 ) }.to raise_error(error_type,error_message)
+    end
+  end
+end
diff --git a/spec/hydra/pcdm/services/collection/remove_related_object_spec.rb b/spec/hydra/pcdm/services/collection/remove_related_object_spec.rb
new file mode 100644
index 00000000..40c9ee7b
--- /dev/null
+++ b/spec/hydra/pcdm/services/collection/remove_related_object_spec.rb
@@ -0,0 +1,146 @@
+require 'spec_helper'
+
+describe Hydra::PCDM::RemoveRelatedObjectFromCollection do
+
+  subject { Hydra::PCDM::Collection.create }
+
+  let(:object1) { Hydra::PCDM::Object.create }
+  let(:object2) { Hydra::PCDM::Object.create }
+  let(:object3) { Hydra::PCDM::Object.create }
+  let(:object4) { Hydra::PCDM::Object.create }
+  let(:object5) { Hydra::PCDM::Object.create }
+
+  let(:collection1) { Hydra::PCDM::Collection.create }
+  let(:collection2) { Hydra::PCDM::Collection.create }
+
+  describe '#call' do
+    context 'when it is the only related object' do
+      before do
+        Hydra::PCDM::AddRelatedObjectToCollection.call( subject, object1 )
+        subject.save
+        expect( Hydra::PCDM::GetRelatedObjectsFromCollection.call( subject.reload )).to eq [object1]
+      end
+
+      it 'should remove related object' do
+        expect( Hydra::PCDM::RemoveRelatedObjectFromCollection.call( subject, object1 ) ).to eq object1
+        expect( Hydra::PCDM::GetRelatedObjectsFromCollection.call( subject.reload )).to eq []
+      end
+
+      it 'should remove related object only when objects & collections' do
+        Hydra::PCDM::AddCollectionToCollection.call( subject, collection1 )
+        Hydra::PCDM::AddCollectionToCollection.call( subject, collection2 )
+        Hydra::PCDM::AddObjectToCollection.call( subject, object3 )
+        Hydra::PCDM::AddObjectToCollection.call( subject, object2 )
+        expect( Hydra::PCDM::RemoveRelatedObjectFromCollection.call( subject, object1 ) ).to eq object1
+        expect( Hydra::PCDM::GetRelatedObjectsFromCollection.call( subject.reload )).to eq []
+        expect( Hydra::PCDM::GetCollectionsFromCollection.call( subject )).to eq [collection1,collection2]
+        expect( Hydra::PCDM::GetObjectsFromCollection.call( subject )).to eq [object3,object2]
+      end
+    end
+
+    context 'when multiple related objects' do
+      before do
+        Hydra::PCDM::AddRelatedObjectToCollection.call( subject, object1 )
+        Hydra::PCDM::AddRelatedObjectToCollection.call( subject, object2 )
+        Hydra::PCDM::AddRelatedObjectToCollection.call( subject, object3 )
+        Hydra::PCDM::AddRelatedObjectToCollection.call( subject, object4 )
+        Hydra::PCDM::AddRelatedObjectToCollection.call( subject, object5 )
+        subject.save
+        expect( Hydra::PCDM::GetRelatedObjectsFromCollection.call( subject.reload )).to eq [object1,object2,object3,object4,object5]
+      end
+
+      it 'should remove first related object' do
+        expect( Hydra::PCDM::RemoveRelatedObjectFromCollection.call( subject, object1 ) ).to eq object1
+        expect( Hydra::PCDM::GetRelatedObjectsFromCollection.call( subject.reload )).to eq [object2,object3,object4,object5]
+      end
+
+      it 'should remove last related object' do
+        expect( Hydra::PCDM::RemoveRelatedObjectFromCollection.call( subject, object5 ) ).to eq object5
+        expect( Hydra::PCDM::GetRelatedObjectsFromCollection.call( subject.reload )).to eq [object1,object2,object3,object4]
+      end
+
+      it 'should remove middle related object' do
+        expect( Hydra::PCDM::RemoveRelatedObjectFromCollection.call( subject, object3 ) ).to eq object3
+        expect( Hydra::PCDM::GetRelatedObjectsFromCollection.call( subject.reload )).to eq [object1,object2,object4,object5]
+      end
+    end
+
+    context 'when related object is missing' do
+      it 'should return nil' do
+        subject.save
+        expect( Hydra::PCDM::RemoveRelatedObjectFromCollection.call( subject.reload, object1 )).to be nil
+      end
+
+      it 'should return nil' do
+        Hydra::PCDM::AddCollectionToCollection.call( subject, collection1 )
+        Hydra::PCDM::AddCollectionToCollection.call( subject, collection2 )
+        Hydra::PCDM::AddObjectToCollection.call( subject, object1 )
+        Hydra::PCDM::AddObjectToCollection.call( subject, object2 )
+        subject.save
+        expect( Hydra::PCDM::RemoveRelatedObjectFromCollection.call( subject.reload, object1 )).to be nil
+      end
+
+      it 'should return nil' do
+        Hydra::PCDM::AddRelatedObjectToCollection.call( subject, object1 )
+        Hydra::PCDM::AddRelatedObjectToCollection.call( subject, object2 )
+        Hydra::PCDM::AddRelatedObjectToCollection.call( subject, object4 )
+        Hydra::PCDM::AddRelatedObjectToCollection.call( subject, object5 )
+        subject.save
+        expect( Hydra::PCDM::RemoveRelatedObjectFromCollection.call( subject.reload, object3 )).to be nil
+      end
+    end
+  end
+
+  context 'with unacceptable related objects' do
+    let(:collection1)     { Hydra::PCDM::Collection.create }
+    let(:file1)           { Hydra::PCDM::File.new }
+    let(:non_PCDM_object) { "I'm not a PCDM object" }
+    let(:af_base_object)  { ActiveFedora::Base.create }
+
+    let(:error_type)    { ArgumentError }
+    let(:error_message) { 'child_related_object must be a pcdm object' }
+
+    it 'should NOT remove Hydra::PCDM::Collections from related_objects aggregation' do
+      expect{ Hydra::PCDM::RemoveRelatedObjectFromCollection.call( subject, collection1 ) }.to raise_error(error_type,error_message)
+    end
+
+    it 'should NOT remove Hydra::PCDM::Files from related_objects aggregation' do
+      expect{ Hydra::PCDM::RemoveRelatedObjectFromCollection.call( subject, file1 ) }.to raise_error(error_type,error_message)
+    end
+
+    it 'should NOT remove non-PCDM objects from related_objects aggregation' do
+      expect{ Hydra::PCDM::RemoveRelatedObjectFromCollection.call( subject, non_PCDM_object ) }.to raise_error(error_type,error_message)
+    end
+
+    it 'should NOT remove AF::Base objects from related_objects aggregation' do
+      expect{ Hydra::PCDM::RemoveRelatedObjectFromCollection.call( subject, af_base_object ) }.to raise_error(error_type,error_message)
+    end
+  end
+
+  context 'with unacceptable parent collection' do
+    let(:object2)          { Hydra::PCDM::Object.create }
+    let(:object1)          { Hydra::PCDM::Object.create }
+    let(:file1)            { Hydra::PCDM::File.new }
+    let(:non_PCDM_object)  { "I'm not a PCDM object" }
+    let(:af_base_object)   { ActiveFedora::Base.create }
+
+    let(:error_type)    { ArgumentError }
+    let(:error_message) { 'parent_collection must be a pcdm collection' }
+
+    it 'should NOT accept Hydra::PCDM::Objects as parent collection' do
+      expect{ Hydra::PCDM::RemoveRelatedObjectFromCollection.call( object1, object2 ) }.to raise_error(error_type,error_message)
+    end
+
+    it 'should NOT accept Hydra::PCDM::Files as parent collection' do
+      expect{ Hydra::PCDM::RemoveRelatedObjectFromCollection.call( file1, object2 ) }.to raise_error(error_type,error_message)
+    end
+
+    it 'should NOT accept non-PCDM objects as parent collection' do
+      expect{ Hydra::PCDM::RemoveRelatedObjectFromCollection.call( non_PCDM_object, object2 ) }.to raise_error(error_type,error_message)
+    end
+
+    it 'should NOT accept AF::Base objects as parent collection' do
+      expect{ Hydra::PCDM::RemoveRelatedObjectFromCollection.call( af_base_object, object2 ) }.to raise_error(error_type,error_message)
+    end
+  end
+end
diff --git a/spec/hydra/pcdm/services/object/add_related_object_spec.rb b/spec/hydra/pcdm/services/object/add_related_object_spec.rb
index 1127ea86..58d2fb03 100644
--- a/spec/hydra/pcdm/services/object/add_related_object_spec.rb
+++ b/spec/hydra/pcdm/services/object/add_related_object_spec.rb
@@ -86,7 +86,8 @@
       let(:object1) { Hydra::PCDM::Object.create }
       let(:object2) { Hydra::PCDM::Object.create }
 
-      xit 'should NOT allow related objects to repeat' do
+      it 'should NOT allow related objects to repeat' do
+        skip 'skipping this test because issue #92 needs to be addressed' do
         Hydra::PCDM::AddRelatedObjectToObject.call( subject, object1 )
         Hydra::PCDM::AddRelatedObjectToObject.call( subject, object2 )
         Hydra::PCDM::AddRelatedObjectToObject.call( subject, object1 )
@@ -95,6 +96,7 @@
         expect( related_objects.include? object2 ).to be true
         expect( related_objects.size ).to eq 2
       end
+      end
     end
   end
 end
diff --git a/spec/hydra/pcdm/services/object/remove_object_spec.rb b/spec/hydra/pcdm/services/object/remove_object_spec.rb
new file mode 100644
index 00000000..47b36bd8
--- /dev/null
+++ b/spec/hydra/pcdm/services/object/remove_object_spec.rb
@@ -0,0 +1,158 @@
+require 'spec_helper'
+
+describe Hydra::PCDM::RemoveObjectFromObject do
+
+  subject { Hydra::PCDM::Object.create }
+
+  let(:object1) { Hydra::PCDM::Object.create }
+  let(:object2) { Hydra::PCDM::Object.create }
+  let(:object3) { Hydra::PCDM::Object.create }
+  let(:object4) { Hydra::PCDM::Object.create }
+  let(:object5) { Hydra::PCDM::Object.create }
+
+  describe '#call' do
+    context 'when it is the only object' do
+      before do
+        Hydra::PCDM::AddObjectToObject.call( subject, object1 )
+        subject.save
+        expect( Hydra::PCDM::GetObjectsFromObject.call( subject.reload )).to eq [object1]
+      end
+
+      it 'should remove object' do
+        expect( Hydra::PCDM::RemoveObjectFromObject.call( subject, object1 ) ).to eq object1
+        expect( Hydra::PCDM::GetObjectsFromObject.call( subject.reload )).to eq []
+      end
+    end
+
+    context 'when multiple objects' do
+      before do
+        Hydra::PCDM::AddObjectToObject.call( subject, object1 )
+        Hydra::PCDM::AddObjectToObject.call( subject, object2 )
+        Hydra::PCDM::AddObjectToObject.call( subject, object3 )
+        Hydra::PCDM::AddObjectToObject.call( subject, object4 )
+        Hydra::PCDM::AddObjectToObject.call( subject, object5 )
+        subject.save
+        expect( Hydra::PCDM::GetObjectsFromObject.call( subject.reload )).to eq [object1,object2,object3,object4,object5]
+      end
+
+      it 'should remove first object' do
+        expect( Hydra::PCDM::RemoveObjectFromObject.call( subject, object1 ) ).to eq object1
+        expect( Hydra::PCDM::GetObjectsFromObject.call( subject.reload )).to eq [object2,object3,object4,object5]
+      end
+
+      it 'should remove last object' do
+        expect( Hydra::PCDM::RemoveObjectFromObject.call( subject, object5 ) ).to eq object5
+        expect( Hydra::PCDM::GetObjectsFromObject.call( subject.reload )).to eq [object1,object2,object3,object4]
+      end
+
+      it 'should remove middle object' do
+        expect( Hydra::PCDM::RemoveObjectFromObject.call( subject, object3 ) ).to eq object3
+        expect( Hydra::PCDM::GetObjectsFromObject.call( subject.reload )).to eq [object1,object2,object4,object5]
+      end
+    end
+
+    context 'when object repeats' do
+      before do
+        Hydra::PCDM::AddObjectToObject.call( subject, object1 )
+        Hydra::PCDM::AddObjectToObject.call( subject, object2 )
+        Hydra::PCDM::AddObjectToObject.call( subject, object3 )
+        Hydra::PCDM::AddObjectToObject.call( subject, object2 )
+        Hydra::PCDM::AddObjectToObject.call( subject, object4 )
+        Hydra::PCDM::AddObjectToObject.call( subject, object2 )
+        Hydra::PCDM::AddObjectToObject.call( subject, object5 )
+        subject.save
+        expect(Hydra::PCDM::GetObjectsFromObject.call( subject )).to eq [object1,object2,object3,object2,object4,object2,object5]
+      end
+
+      it 'should remove first occurrence' do
+        skip 'skipping this test because issue #102 needs to be addressed' do
+        expect( Hydra::PCDM::RemoveObjectFromObject.call( subject, object2 ) ).to eq object2
+        expect( Hydra::PCDM::GetObjectsFromObject.call( subject.reload )).to eq [object1,object3,object2,object4,object2,object5]
+      end
+      end
+
+      it 'should remove last occurrence' do
+        skip 'skipping this test because issue #102 needs to be addressed' do
+        expect( Hydra::PCDM::RemoveObjectFromObject.call( subject, object2, -1 ) ).to eq object2
+        expect( Hydra::PCDM::GetObjectsFromObject.call( subject.reload )).to eq [object1,object2,object3,object2,object4,object5]
+      end
+      end
+
+      it 'should remove nth occurrence' do
+        skip 'skipping this test because issue #102 needs to be addressed' do
+        expect( Hydra::PCDM::RemoveObjectFromObject.call( subject, object2, 2 ) ).to eq object2
+        expect( Hydra::PCDM::GetObjectsFromObject.call( subject.reload )).to eq [object1,object2,object3,object4,object2,object5]
+      end
+      end
+    end
+
+    context 'when object is missing' do
+      it 'should return nil' do
+        subject.save
+        expect( Hydra::PCDM::RemoveObjectFromObject.call( subject.reload, object1 )).to be nil
+      end
+
+      it 'should return nil' do
+        Hydra::PCDM::AddObjectToObject.call( subject, object1 )
+        Hydra::PCDM::AddObjectToObject.call( subject, object2 )
+        Hydra::PCDM::AddObjectToObject.call( subject, object4 )
+        Hydra::PCDM::AddObjectToObject.call( subject, object5 )
+        subject.save
+        expect( Hydra::PCDM::RemoveObjectFromObject.call( subject.reload, object3 )).to be nil
+      end
+    end
+  end
+
+  context 'with unacceptable objects' do
+    let(:collection1)     { Hydra::PCDM::Collection.create }
+    let(:file1)           { Hydra::PCDM::File.new }
+    let(:non_PCDM_object) { "I'm not a PCDM object" }
+    let(:af_base_object)  { ActiveFedora::Base.create }
+
+    let(:error_type)    { ArgumentError }
+    let(:error_message) { 'child_object must be a pcdm object' }
+
+    it 'should NOT remove Hydra::PCDM::Collections from objects aggregation' do
+      expect{ Hydra::PCDM::RemoveObjectFromObject.call( subject, collection1 ) }.to raise_error(error_type,error_message)
+    end
+
+    it 'should NOT remove Hydra::PCDM::Files from objects aggregation' do
+      expect{ Hydra::PCDM::RemoveObjectFromObject.call( subject, file1 ) }.to raise_error(error_type,error_message)
+    end
+
+    it 'should NOT remove non-PCDM objects from objects aggregation' do
+      expect{ Hydra::PCDM::RemoveObjectFromObject.call( subject, non_PCDM_object ) }.to raise_error(error_type,error_message)
+    end
+
+    it 'should NOT remove AF::Base objects from objects aggregation' do
+      expect{ Hydra::PCDM::RemoveObjectFromObject.call( subject, af_base_object ) }.to raise_error(error_type,error_message)
+    end
+  end
+
+  context 'with unacceptable parent object' do
+    let(:object2)          { Hydra::PCDM::Object.create }
+    let(:collection1)      { Hydra::PCDM::Collection.create }
+    let(:file1)            { Hydra::PCDM::File.new }
+    let(:non_PCDM_object)  { "I'm not a PCDM object" }
+    let(:af_base_object)   { ActiveFedora::Base.create }
+
+    let(:error_type)    { ArgumentError }
+    let(:error_message) { 'parent_object must be a pcdm object' }
+
+    it 'should NOT accept Hydra::PCDM::Collections as parent object' do
+      expect{ Hydra::PCDM::RemoveObjectFromObject.call( collection1, object2 ) }.to raise_error(error_type,error_message)
+    end
+
+    it 'should NOT accept Hydra::PCDM::Files as parent object' do
+      expect{ Hydra::PCDM::RemoveObjectFromObject.call( file1, object2 ) }.to raise_error(error_type,error_message)
+    end
+
+    it 'should NOT accept non-PCDM objects as parent object' do
+      expect{ Hydra::PCDM::RemoveObjectFromObject.call( non_PCDM_object, object2 ) }.to raise_error(error_type,error_message)
+    end
+
+    it 'should NOT accept AF::Base objects as parent object' do
+      expect{ Hydra::PCDM::RemoveObjectFromObject.call( af_base_object, object2 ) }.to raise_error(error_type,error_message)
+    end
+  end
+end
diff --git a/spec/hydra/pcdm/services/object/remove_related_object_spec.rb b/spec/hydra/pcdm/services/object/remove_related_object_spec.rb
new file mode 100644
index 00000000..16eb0a8b
--- /dev/null
+++ b/spec/hydra/pcdm/services/object/remove_related_object_spec.rb
@@ -0,0 +1,126 @@
+require 'spec_helper'
+
+describe Hydra::PCDM::RemoveRelatedObjectFromObject do
+
+  subject { Hydra::PCDM::Object.create }
+
+  let(:object1) { Hydra::PCDM::Object.create }
+  let(:object2) { Hydra::PCDM::Object.create }
+  let(:object3) { Hydra::PCDM::Object.create }
+  let(:object4) { Hydra::PCDM::Object.create }
+  let(:object5) { Hydra::PCDM::Object.create }
+
+  let(:file1) { Hydra::PCDM::File.new }
+  let(:file2) { Hydra::PCDM::File.new }
+
+  describe '#call' do
+    context 'when it is the only related object' do
+      before do
+        Hydra::PCDM::AddRelatedObjectToObject.call( subject, object1 )
+        subject.save
+        expect( Hydra::PCDM::GetRelatedObjectsFromObject.call( subject.reload )).to eq [object1]
+      end
+
+      it 'should remove related object' do
+        expect( Hydra::PCDM::RemoveRelatedObjectFromObject.call( subject, object1 ) ).to eq object1
+        expect( Hydra::PCDM::GetRelatedObjectsFromObject.call( subject.reload )).to eq []
+      end
+    end
+
+    context 'when multiple related objects' do
+      before do
+        Hydra::PCDM::AddRelatedObjectToObject.call( subject, object1 )
+        Hydra::PCDM::AddRelatedObjectToObject.call( subject, object2 )
+        Hydra::PCDM::AddRelatedObjectToObject.call( subject, object3 )
+        Hydra::PCDM::AddRelatedObjectToObject.call( subject, object4 )
+        Hydra::PCDM::AddRelatedObjectToObject.call( subject, object5 )
+        subject.save
+        expect( Hydra::PCDM::GetRelatedObjectsFromObject.call( subject.reload )).to eq [object1,object2,object3,object4,object5]
+      end
+
+      it 'should remove first related object' do
+        expect( Hydra::PCDM::RemoveRelatedObjectFromObject.call( subject, object1 ) ).to eq object1
+        expect( Hydra::PCDM::GetRelatedObjectsFromObject.call( subject.reload )).to eq [object2,object3,object4,object5]
+      end
+
+      it 'should remove last related object' do
+        expect( Hydra::PCDM::RemoveRelatedObjectFromObject.call( subject, object5 ) ).to eq object5
+        expect( Hydra::PCDM::GetRelatedObjectsFromObject.call( subject.reload )).to eq [object1,object2,object3,object4]
+      end
+
+      it 'should remove middle related object' do
+        expect( Hydra::PCDM::RemoveRelatedObjectFromObject.call( subject, object3 ) ).to eq object3
+        expect( Hydra::PCDM::GetRelatedObjectsFromObject.call( subject.reload )).to eq [object1,object2,object4,object5]
+      end
+    end
+
+    context 'when related object is missing' do
+      it 'should return nil' do
+        subject.save
+        expect( Hydra::PCDM::RemoveRelatedObjectFromObject.call( subject.reload, object1 )).to be nil
+      end
+
+      it 'should return nil' do
+        Hydra::PCDM::AddRelatedObjectToObject.call( subject, object1 )
+        Hydra::PCDM::AddRelatedObjectToObject.call( subject, object2 )
+        Hydra::PCDM::AddRelatedObjectToObject.call( subject, object4 )
+        Hydra::PCDM::AddRelatedObjectToObject.call( subject, object5 )
+        subject.save
+        expect( Hydra::PCDM::RemoveRelatedObjectFromObject.call( subject.reload, object3 )).to be nil
+      end
+    end
+  end
+
+  context 'with unacceptable related objects' do
+    let(:collection1)     { Hydra::PCDM::Collection.create }
+    let(:file1)           { Hydra::PCDM::File.new }
+    let(:non_PCDM_object) { "I'm not a PCDM object" }
+    let(:af_base_object)  { ActiveFedora::Base.create }
+
+    let(:error_type)    { ArgumentError }
+    let(:error_message) { 'child_related_object must be a pcdm object' }
+
+    it 'should NOT remove Hydra::PCDM::Collections from related_objects aggregation' do
+      expect{ Hydra::PCDM::RemoveRelatedObjectFromObject.call( subject, collection1 ) }.to raise_error(error_type,error_message)
+    end
+
+    it 'should NOT remove Hydra::PCDM::Files from related_objects aggregation' do
+      expect{ Hydra::PCDM::RemoveRelatedObjectFromObject.call( subject, file1 ) }.to raise_error(error_type,error_message)
+    end
+
+    it 'should NOT remove non-PCDM objects from related_objects aggregation' do
+      expect{ Hydra::PCDM::RemoveRelatedObjectFromObject.call( subject, non_PCDM_object ) }.to raise_error(error_type,error_message)
+    end
+
+    it 'should NOT remove AF::Base objects from related_objects aggregation' do
+      expect{ Hydra::PCDM::RemoveRelatedObjectFromObject.call( subject, af_base_object ) }.to raise_error(error_type,error_message)
+    end
+  end
+
+  context 'with unacceptable parent object' do
+    let(:object2)          { Hydra::PCDM::Object.create }
+    let(:collection1)      { Hydra::PCDM::Collection.create }
+    let(:file1)            { Hydra::PCDM::File.new }
+    let(:non_PCDM_object)  { "I'm not a PCDM object" }
+    let(:af_base_object)   { ActiveFedora::Base.create }
+
+    let(:error_type)    { ArgumentError }
+    let(:error_message) { 'parent_object must be a pcdm object' }
+
+    it 'should NOT accept Hydra::PCDM::Objects as parent object' do
+      expect{ Hydra::PCDM::RemoveRelatedObjectFromObject.call( collection1, object2 ) }.to raise_error(error_type,error_message)
+    end
+
+    it 'should NOT accept Hydra::PCDM::Files as parent object' do
+      expect{ Hydra::PCDM::RemoveRelatedObjectFromObject.call( file1, object2 ) }.to raise_error(error_type,error_message)
+    end
+
+    it 'should NOT accept non-PCDM objects as parent object' do
+      expect{ Hydra::PCDM::RemoveRelatedObjectFromObject.call( non_PCDM_object, object2 ) }.to raise_error(error_type,error_message)
+    end
+
+    it 'should NOT accept AF::Base objects as parent object' do
+      expect{ Hydra::PCDM::RemoveRelatedObjectFromObject.call( af_base_object, object2 ) }.to raise_error(error_type,error_message)
+    end
+  end
+end