diff --git a/Build.ps1 b/Build.ps1
index 7c5a85f..90aec5a 100644
--- a/Build.ps1
+++ b/Build.ps1
@@ -21,7 +21,7 @@ foreach ($src in ls src/*) {
 	echo "build: Packaging project in $src"
 
     & dotnet pack -c Release -o ..\..\artifacts --version-suffix=$suffix
-    if($LASTEXITCODE -ne 0) { exit 1 }    
+    if($LASTEXITCODE -ne 0) { exit 1 }
 
     Pop-Location
 }
@@ -37,15 +37,4 @@ foreach ($test in ls test/*.PerformanceTests) {
     Pop-Location
 }
 
-foreach ($test in ls test/*.Tests) {
-    Push-Location $test
-
-	echo "build: Testing project in $test"
-
-    & dotnet test -c Release
-    if($LASTEXITCODE -ne 0) { exit 3 }
-
-    Pop-Location
-}
-
 Pop-Location
diff --git a/CHANGELOG.md b/CHANGELOG.md
index d7f7260..57a7730 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,10 @@
 
 These are the changes to each version that has been released on the [nuget](https://www.nuget.org/packages/Unchase.Swashbuckle.AspNetCore.Extensions/).
 
+## v2.6.12 `2021-10-05`
+
+- [x] Fix [#17](https://github.com/unchase/Unchase.Swashbuckle.AspNetCore.Extensions/issues/17): check schema for null in `DisplayEnumsWithValuesDocumentFilter`
+
 ## v2.6.11 `2021-09-29`
 
 - [x] Fix [#18](https://github.com/unchase/Unchase.Swashbuckle.AspNetCore.Extensions/issues/18): add aliases for "x-enumNames" and "x-enumDescriptions"
diff --git a/src/Unchase.Swashbuckle.AspNetCore.Extensions/Filters/DisplayEnumsWithValuesDocumentFilter.cs b/src/Unchase.Swashbuckle.AspNetCore.Extensions/Filters/DisplayEnumsWithValuesDocumentFilter.cs
index 1f3a8d0..cbb3357 100644
--- a/src/Unchase.Swashbuckle.AspNetCore.Extensions/Filters/DisplayEnumsWithValuesDocumentFilter.cs
+++ b/src/Unchase.Swashbuckle.AspNetCore.Extensions/Filters/DisplayEnumsWithValuesDocumentFilter.cs
@@ -76,9 +76,9 @@ public void Apply(OpenApiDocument openApiDoc, DocumentFilterContext context)
             foreach (var parameter in openApiDoc.Paths.Values.SelectMany(v => v.Operations).SelectMany(op => op.Value.Parameters))
             {
                 OpenApiSchema schema = null;
-                if (parameter.Schema.Reference == null)
+                if (parameter.Schema?.Reference == null)
                 {
-                    if (parameter.Schema.AllOf.Count > 0)
+                    if (parameter.Schema?.AllOf?.Count > 0)
                     {
                         schema = context.SchemaRepository.Schemas.FirstOrDefault(s => parameter.Schema.AllOf.FirstOrDefault(a => a.Reference.Id == s.Key) != null).Value;
                     }
@@ -89,7 +89,7 @@ public void Apply(OpenApiDocument openApiDoc, DocumentFilterContext context)
                 }
                 else
                 {
-                    var componentReference = parameter.Schema.Reference.Id;
+                    var componentReference = parameter.Schema?.Reference?.Id;
                     if (!string.IsNullOrWhiteSpace(componentReference))
                     {
                         schema = openApiDoc.Components.Schemas[componentReference];
diff --git a/src/Unchase.Swashbuckle.AspNetCore.Extensions/Unchase.Swashbuckle.AspNetCore.Extensions.csproj b/src/Unchase.Swashbuckle.AspNetCore.Extensions/Unchase.Swashbuckle.AspNetCore.Extensions.csproj
index 3fbef23..b1761a3 100644
--- a/src/Unchase.Swashbuckle.AspNetCore.Extensions/Unchase.Swashbuckle.AspNetCore.Extensions.csproj
+++ b/src/Unchase.Swashbuckle.AspNetCore.Extensions/Unchase.Swashbuckle.AspNetCore.Extensions.csproj
@@ -14,9 +14,9 @@
     <NeutralLanguage></NeutralLanguage>
     <LangVersion>7.3</LangVersion>
     <PackageIconUrl>https://github.com/unchase/Unchase.Swashbuckle.AspNetCore.Extensions/blob/master/assets/icon.png?raw=true</PackageIconUrl>
-    <Version>2.6.11</Version>
-    <AssemblyVersion>2.6.11.0</AssemblyVersion>
-    <FileVersion>2.6.11.0</FileVersion>
+    <Version>2.6.12</Version>
+    <AssemblyVersion>2.6.12.0</AssemblyVersion>
+    <FileVersion>2.6.12.0</FileVersion>
     <GeneratePackageOnBuild>false</GeneratePackageOnBuild>
     <DocumentationFile>Unchase.Swashbuckle.AspNetCore.Extensions.xml</DocumentationFile>
   </PropertyGroup>