diff --git a/.gitignore b/.gitignore
index a52216f..4f5e020 100644
--- a/.gitignore
+++ b/.gitignore
@@ -11,8 +11,5 @@
 # Output of the go coverage tool, specifically when used with LiteIDE
 *.out
 
-# Binaries
-bin/
-
-# Custom
-serverless-installer-answers.yaml
+# Build
+build
diff --git a/.travis.yml b/.travis.yml
index 992c0d4..90963c4 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,17 +1,21 @@
 language: go
 sudo: false
+dist: trusty
 go:
- - 1.13.x
-matrix:
-  fast_finish: true
-  include:
-    - env: GOOS="linux"
-    - env: GOOS="windows"
-    - env: GOOS="darwin"
+  - 1.13.x
+script:
+  - make clean binary
+  - sonar-scanner
 branches:
   only:
-    - master
-    - develop
-    - /^v\d/
+  - master
+  - develop
+  - "/^v\\d/"
 notifications:
   email: onchange
+addons:
+  sonarcloud:
+    organization: "wavesoftware"
+    token:
+			secure: "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"
+
diff --git a/Makefile b/Makefile
index 98b0932..66e1104 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,7 @@
-PROJECT_DIR = "./"
+PROJECT_DIR = $(shell readlink -f .)
 CLI_DIR     = "$(PROJECT_DIR)/cmd/installer"
-BIN         = "$(PROJECT_DIR)/bin/serverless-installer"
+BUILD_DIR   = "$(PROJECT_DIR)/build"
+BIN         = "$(BUILD_DIR)/serverless-installer"
 
 GO           ?= go
 GOLINT       ?= $(GO)lint
@@ -9,7 +10,7 @@ RICHGO       ?= rich$(GO)
 RESET          = \033[0m
 make_std_color = \033[3$1m      # defined for 1 through 7
 make_color     = \033[38;5;$1m  # defined for 1 through 255
-BLUE = $(strip $(call make_color,44))
+BLUE = $(strip $(call make_color,38))
 PINK = $(strip $(call make_color,210))
 RED = $(strip $(call make_color,206))
 GREEN = $(strip $(call make_color,120))
@@ -24,27 +25,31 @@ builddeps:
 	@$(GO) get github.com/kyoh86/richgo
 	@$(GO) get golang.org/x/lint/golint
 
+.PHONY: builddir
+builddir:
+	@mkdir -p build
+
 .PHONY: clean
 clean: builddeps
 	@echo " $(GRAY)🛁 Cleaning$(RESET)"
-	@rm -fv $(BIN)
+	@rm -frv $(BUILD_DIR)
 
 .PHONY: check
 check: builddeps
-	@echo " $(PINK)🛂 Checking$(RESET)"
+	@echo " $(PINK)👮 Checking$(RESET)"
 	$(GOLINT) -set_exit_status ./...
 
 .PHONY: test
-test: check
+test: builddir check
 	@echo " $(GREEN)✔️ Testing$(RESET)"
-	$(RICHGO) test -cover ./...
+	$(RICHGO) test -covermode=count -coverprofile=build/coverage.out ./...
 
 .PHONY: binary
-binary: test
+binary: builddir test
 	@echo " $(BLUE)🔨 Building$(RESET)"
 	$(RICHGO) build -o $(BIN) $(CLI_DIR)
 
 .PHONY: run
-run: binary
+run: builddir binary
 	@echo " $(RED)🏃 Running$(RESET)"
-	$(BIN) $(args)
+	cd $(BUILD_DIR) && $(BIN) $(args)
diff --git a/go.mod b/go.mod
index 15a177f..c8db727 100644
--- a/go.mod
+++ b/go.mod
@@ -7,11 +7,14 @@ require (
 	github.com/Bowery/prompt v0.0.0-20190916142128-fa8279994f75 // indirect
 	github.com/google/uuid v1.1.1
 	github.com/kr/pretty v0.1.0 // indirect
+	github.com/kyoh86/richgo v0.3.3 // indirect
 	github.com/labstack/gommon v0.3.0 // indirect
 	github.com/mattn/go-colorable v0.1.4 // indirect
 	github.com/mkideal/cli v0.0.3
 	github.com/mkideal/pkg v0.0.0-20170503154153-3e188c9e7ecc // indirect
 	github.com/sirupsen/logrus v1.4.2
+	github.com/stretchr/testify v1.4.0
+	golang.org/x/lint v0.0.0-20190930215403-16217165b5de // indirect
 	golang.org/x/sys v0.0.0-20191002091554-b397fe3ad8ed // indirect
 	gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 // indirect
 	gopkg.in/yaml.v2 v2.2.4
diff --git a/go.sum b/go.sum
index 139700d..b49649f 100644
--- a/go.sum
+++ b/go.sum
@@ -7,6 +7,9 @@ github.com/Netflix/go-expect v0.0.0-20180615182759-c93bf25de8e8/go.mod h1:oX5x61
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/deadcheat/goblet v1.3.1/go.mod h1:IrMNyAwyrVgB30HsND2WgleTUM4wHTS9m40yNY6NJQg=
+github.com/deadcheat/gonch v0.0.0-20180528124129-c2ff7a019863/go.mod h1:/5mH3gAuXUxGN3maOBAxBfB8RXvP9tBIX5fx2x1k0V0=
+github.com/golang/mock v1.1.1/go.mod h1:oTYuIxOrZwtPieC+H1uAHpcLFnEyAGVDL/k47Jfbm0A=
 github.com/google/uuid v1.1.1 h1:Gkbcsh/GbpXz7lPftLA3P6TYMwjCLYm83jiFQZF/3gY=
 github.com/google/uuid v1.1.1/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/hinshun/vt10x v0.0.0-20180616224451-1954e6464174 h1:WlZsjVhE8Af9IcZDGgJGQpNflI3+MJSBhsgT5PCtzBQ=
@@ -22,11 +25,16 @@ github.com/kr/pty v1.1.4 h1:5Myjjh3JY/NaAi4IsUbHADytDyl1VE1Y9PXDlL+P/VQ=
 github.com/kr/pty v1.1.4/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
+github.com/kyoh86/richgo v0.3.3 h1:fW7ygWNMg1INcX3Yoha9v1C5nYlvd/IodJUf0Batz6Q=
+github.com/kyoh86/richgo v0.3.3/go.mod h1:S65jllVRxBm59fqIXfCa3cPxQYRT9u9v45EPQVeuoH0=
+github.com/kyoh86/xdg v0.0.0-20171007020617-d28e4c5d7b81 h1:C2Yb5TxdHWrtWXdf+j8xWW4QQu8lXuxtj1UOK816dpA=
+github.com/kyoh86/xdg v0.0.0-20171007020617-d28e4c5d7b81/go.mod h1:Z5mDqe0fxyxn3W2yTxsBAOQqIrXADQIh02wrTnaRM38=
 github.com/labstack/gommon v0.3.0 h1:JEeO0bvc78PKdyHxloTKiF8BD5iGrH8T6MSeGvSgob0=
 github.com/labstack/gommon v0.3.0/go.mod h1:MULnywXg0yavhxWKc+lOruYdAhDwPK9wf0OL7NoOu+k=
 github.com/mattn/go-colorable v0.1.2/go.mod h1:U0ppj6V5qS13XJ6of8GYAs25YV2eR4EVcfRqFIhoBtE=
 github.com/mattn/go-colorable v0.1.4 h1:snbPLB8fVfU9iwbbo30TPtbLRzwWu6aJS6Xh4eaaviA=
 github.com/mattn/go-colorable v0.1.4/go.mod h1:U0ppj6V5qS13XJ6of8GYAs25YV2eR4EVcfRqFIhoBtE=
+github.com/mattn/go-isatty v0.0.0-20170925054904-a5cdd64afdee/go.mod h1:M+lRXTBqGeGNdLjl/ufCoiOlB5xdOkqRJdNxMWT7Zi4=
 github.com/mattn/go-isatty v0.0.8/go.mod h1:Iq45c/XA43vh69/j3iqttzPXn0bhXyGjM0Hdxcsrc5s=
 github.com/mattn/go-isatty v0.0.9 h1:d5US/mDsogSGW37IV293h//ZFaeajb69h+EHFsv2xGg=
 github.com/mattn/go-isatty v0.0.9/go.mod h1:YNRxwqDuOph6SZLI9vUUz6OYw3QyUt7WiY2yME+cCiQ=
@@ -36,22 +44,33 @@ github.com/mkideal/cli v0.0.3 h1:Y1OXyfTVI9eQ9RTiXq12h7q88y22Q9ZU4VI09ifz6lE=
 github.com/mkideal/cli v0.0.3/go.mod h1:HLuSls75T7LFlTgByGeuLwcvdUmmx/aUQxnnEKxoZzY=
 github.com/mkideal/pkg v0.0.0-20170503154153-3e188c9e7ecc h1:eyN9UWVX+CeeCQZPudCUAPc84xQYTjEu9MWNa2HuJrs=
 github.com/mkideal/pkg v0.0.0-20170503154153-3e188c9e7ecc/go.mod h1:DECgB56amjU/mmmsKuooNPQ1856HASOMC3D4ntSVU70=
+github.com/morikuni/aec v0.0.0-20170113033406-39771216ff4c h1:nXxl5PrvVm2L/wCy8dQu6DMTwH4oIuGN8GJDAlqDdVE=
+github.com/morikuni/aec v0.0.0-20170113033406-39771216ff4c/go.mod h1:BbKIizmSmc5MMPqRYbxO4ZU0S0+P200+tUnFx7PXmsc=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/sirupsen/logrus v1.4.2 h1:SPIRibHv4MatM3XXNO2BJeFLZwZ2LvZgfQ5+UNI2im4=
 github.com/sirupsen/logrus v1.4.2/go.mod h1:tLMulIdttU9McNUspp0xgXVQah82FyeX6MwdIuYE2rE=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.1.4/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.2.1/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.4.0 h1:2E4SXV/wtOkTonXsotYi4li6zVWxYlZuYNCXe9XRJyk=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
+github.com/urfave/cli v1.20.0/go.mod h1:70zkFmudgCuE/ngEzBv17Jvp/497gISqfk5gWijbERA=
 github.com/valyala/bytebufferpool v1.0.0/go.mod h1:6bBcMArwyJ5K/AmCkWv1jt77kVWyCJ6HpOuEn7z0Csc=
 github.com/valyala/fasttemplate v1.0.1/go.mod h1:UQGH1tvbgY+Nz5t2n7tXsz52dQxojPUpymEIMZ47gx8=
+github.com/wacul/ptr v0.0.0-20170209030335-91632201dfc8 h1:js9Z9dWq50Ttu4D1YRqgS1gkSgRfpKp+rMza4io7qNw=
+github.com/wacul/ptr v0.0.0-20170209030335-91632201dfc8/go.mod h1:BD0gjsZrCwtoR+yWDB9v2hQ8STlq9tT84qKfa+3txOc=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20190530122614-20be4c3c3ed5 h1:8dUaAV7K4uHsF56JQWkprecIQKdPHtR9jCHF5nB8uzc=
 golang.org/x/crypto v0.0.0-20190530122614-20be4c3c3ed5/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
+golang.org/x/lint v0.0.0-20190930215403-16217165b5de h1:5hukYrvBGR8/eNkX5mdUezrA6JiaEZDtJb9Ei+1LlBs=
+golang.org/x/lint v0.0.0-20190930215403-16217165b5de/go.mod h1:6SW0HCj/g11FgYtHlgUYUwCkIfeOF89ocIRzGO/8vkc=
+golang.org/x/net v0.0.0-20180404174746-b3c676e531a6/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
+golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/sys v0.0.0-20170927054621-314a259e304f/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190222072716-a9d3bda3a223/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
@@ -62,10 +81,13 @@ golang.org/x/sys v0.0.0-20190813064441-fde4db37ae7a/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20191002091554-b397fe3ad8ed h1:5TJcLJn2a55mJjzYk0yOoqN8X1OdvBDUnaZaKKyQtkY=
 golang.org/x/sys v0.0.0-20191002091554-b397fe3ad8ed/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/tools v0.0.0-20190311212946-11955173bddd h1:/e+gpKk9r3dJobndpTytxS2gOy6m5uvpg+ISQoEcusQ=
+golang.org/x/tools v0.0.0-20190311212946-11955173bddd/go.mod h1:LCzVGOaR6xXOjkQ3onu1FJEFr0SW1gC7cKk1uF8kGRs=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 h1:qIbj1fsPNlZgppZ+VLlY7N33q108Sa+fhmuc+sWQYwY=
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v2 v2.0.0-20170812160011-eb3733d160e7/go.mod h1:JAlM8MvJe8wmxCU4Bli9HhUf9+ttbYbLASfIpnQbh74=
 gopkg.in/yaml.v2 v2.2.2 h1:ZCJp+EgiOT7lHqUV2J862kp8Qj64Jo6az82+3Td9dZw=
 gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.4 h1:/eiJrUcujPVeJ3xlSWaiNi3uSVmDGBK1pDHUHAnao1I=
diff --git a/internal/domain/contract/answers_test.go b/internal/domain/contract/answers_test.go
new file mode 100644
index 0000000..dec0b83
--- /dev/null
+++ b/internal/domain/contract/answers_test.go
@@ -0,0 +1,15 @@
+package contract
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestStruct(t *testing.T) {
+	// when
+	answers := LocationAwareAnswers{}
+
+	// then
+	assert.NotNil(t, answers)
+}
diff --git a/internal/domain/logic/answers.go b/internal/domain/logic/answers.go
index ab2977d..9834122 100644
--- a/internal/domain/logic/answers.go
+++ b/internal/domain/logic/answers.go
@@ -4,6 +4,7 @@ import (
 	log "github.com/sirupsen/logrus"
 	yaml "gopkg.in/yaml.v2"
 
+	"github.com/wavesoftware/serverless-installer/internal"
 	"github.com/wavesoftware/serverless-installer/internal/domain/gateway"
 	"github.com/wavesoftware/serverless-installer/internal/domain/model"
 )
@@ -18,9 +19,7 @@ func (service answersService) Save(answers model.Answers, path string) error {
 		WithField("answers", answers).
 		Debug("Saved called")
 	contents, err := yaml.Marshal(answers)
-	if err != nil {
-		return err
-	}
+	internal.CheckNil("20191004:135106", err)
 	log.
 		WithField("yaml", string(contents)).
 		Trace("Yaml")
diff --git a/internal/domain/logic/answers_test.go b/internal/domain/logic/answers_test.go
new file mode 100644
index 0000000..ac44cfc
--- /dev/null
+++ b/internal/domain/logic/answers_test.go
@@ -0,0 +1,64 @@
+package logic
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/wavesoftware/serverless-installer/internal/domain/model"
+)
+
+var files []file
+
+func TestSave(t *testing.T) {
+	// given
+	files = nil
+	service := answersService{
+		fileWriter: stubWriter{},
+	}
+	answers := model.Answers{}
+	answers.Jeager.Install.Enabled = false
+	path := "/tmp/answers.yaml"
+	expectedYaml := strings.ReplaceAll(`jeager:
+	install:
+		enabled: false
+elasticsearch:
+	install:
+		enabled: false
+kiali:
+	install:
+		enabled: false
+istio:
+	install:
+		enabled: false
+serverless:
+	install:
+		enabled: false
+`, "\t", "  ")
+
+	// when
+	err := service.Save(answers, path)
+
+	// then
+	assert.Nil(t, err)
+	assert.Len(t, files, 1)
+	first := files[0]
+	assert.Equal(t, path, first.path)
+	assert.Equal(t, expectedYaml, string(first.contents))
+}
+
+type file struct {
+	contents []byte
+	path     string
+}
+
+type stubWriter struct{}
+
+func (w stubWriter) Write(contents []byte, path string) error {
+	files = append(files, file{
+		contents: contents,
+		path:     path,
+	})
+	return nil
+}
diff --git a/internal/domain/logic/factories_test.go b/internal/domain/logic/factories_test.go
new file mode 100644
index 0000000..d726055
--- /dev/null
+++ b/internal/domain/logic/factories_test.go
@@ -0,0 +1,15 @@
+package logic
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCreateAnswersSaver(t *testing.T) {
+	// when
+	saver := CreateAnswersSaver()
+
+	// then
+	assert.NotNil(t, saver)
+}
diff --git a/internal/domain/model/answers_test.go b/internal/domain/model/answers_test.go
new file mode 100644
index 0000000..e073ede
--- /dev/null
+++ b/internal/domain/model/answers_test.go
@@ -0,0 +1,15 @@
+package model
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestStruct(t *testing.T) {
+	// when
+	answers := Answers{}
+
+	// then
+	assert.NotNil(t, answers)
+}
diff --git a/internal/persistence/factories_test.go b/internal/persistence/factories_test.go
new file mode 100644
index 0000000..8f8d19d
--- /dev/null
+++ b/internal/persistence/factories_test.go
@@ -0,0 +1,15 @@
+package persistence
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCreateFileWriter(t *testing.T) {
+	// when
+	writer := CreateFileWriter()
+
+	// then
+	assert.NotNil(t, writer)
+}
diff --git a/internal/persistence/filesystem_test.go b/internal/persistence/filesystem_test.go
index f4ce87f..e2c380e 100644
--- a/internal/persistence/filesystem_test.go
+++ b/internal/persistence/filesystem_test.go
@@ -7,6 +7,7 @@ import (
 	"testing"
 
 	"github.com/google/uuid"
+	"github.com/stretchr/testify/assert"
 
 	"github.com/wavesoftware/serverless-installer/internal/domain/contract"
 )
@@ -14,7 +15,7 @@ import (
 func TestFilesystemWriter(t *testing.T) {
 	// given
 	tmp, err := ioutil.TempDir("", "test-filesystem-writer")
-	checkNoError(err)
+	assert.Nil(t, err)
 	defer os.RemoveAll(tmp)
 	writer := filesystemWriter{}
 	path := filepath.Join(tmp, uuid.New().String(), contract.AnswersFilename)
@@ -24,13 +25,22 @@ func TestFilesystemWriter(t *testing.T) {
 	err = writer.Write(contents, path)
 
 	// then
-	if err != nil {
-		t.Error(err)
-	}
+	assert.Nil(t, err)
 }
 
-func checkNoError(err error) {
-	if err != nil {
-		panic(err)
-	}
+func TestFilesystemWriterOnInvalidPath(t *testing.T) {
+	// given
+	writer := filesystemWriter{}
+	path := filepath.Join(
+		// invalid character in path 0x0
+		string([]byte{0x0}),
+		uuid.New().String(), contract.AnswersFilename,
+	)
+	contents := []byte("This is test")
+
+	// when
+	err := writer.Write(contents, path)
+
+	// then
+	assert.NotNil(t, err)
 }
diff --git a/internal/preconditions.go b/internal/preconditions.go
new file mode 100644
index 0000000..0f5171c
--- /dev/null
+++ b/internal/preconditions.go
@@ -0,0 +1,24 @@
+package internal
+
+import (
+	"fmt"
+	"reflect"
+
+	log "github.com/sirupsen/logrus"
+)
+
+// CheckNil - Checks if given value is nil as expected, panics otherwise
+func CheckNil(eid string, val interface{}) {
+	if !isNil(val) {
+		message := fmt.Sprintf(
+			"[%s] checkNil: Received a non nil value \"%v\", but not expecting that. A bug propably!",
+			eid, val,
+		)
+		log.Panic(message)
+		panic(message)
+	}
+}
+
+func isNil(val interface{}) bool {
+	return val == nil || (reflect.ValueOf(val).Kind() == reflect.Ptr && reflect.ValueOf(val).IsNil())
+}
diff --git a/internal/preconditions_test.go b/internal/preconditions_test.go
new file mode 100644
index 0000000..0aa98cf
--- /dev/null
+++ b/internal/preconditions_test.go
@@ -0,0 +1,30 @@
+package internal
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCheckNil(t *testing.T) {
+	// given
+	eid := "20191004:135407"
+	var value error = nil
+
+	// when
+	CheckNil(eid, value)
+}
+
+func TestCheckNilOnValue(t *testing.T) {
+	// given
+	eid := "20191004:140503"
+	var value error = errors.New("Some error")
+	defer func() {
+		r := recover()
+		assert.NotNil(t, r)
+	}()
+
+	// when
+	CheckNil(eid, value)
+}
diff --git a/sonar-project.properties b/sonar-project.properties
new file mode 100644
index 0000000..5d2a730
--- /dev/null
+++ b/sonar-project.properties
@@ -0,0 +1,14 @@
+sonar.projectKey=wavesoftware_serverless-installer
+# this is the name and version displayed in the SonarCloud UI.
+sonar.projectName=Serverless Installer
+sonar.projectVersion=1.0.0-pre
+ 
+# Encoding of the source code. Default is default system encoding
+sonar.sourceEncoding=UTF-8
+
+sonar.sources=.
+sonar.exclusions=**/*_test.go,**/vendor/**
+
+sonar.tests=.
+sonar.test.inclusions=**/*_test.go
+sonar.test.exclusions=**/vendor/**