implement slice unique elemets assertsion (#34)

assert/bool.go

@@ -24,6 +24,7 @@ func ThatBool(t *testing.T, actual bool) AssertableBool {
 // IsEqualTo asserts if the expected bool is equal to the assertable bool value
 // It errors the tests if the compared values (actual VS expected) are not equal.
 func (a AssertableBool) IsEqualTo(expected interface{}) AssertableBool {
+	a.t.Helper()
 	if !a.actual.IsEqualTo(expected) {
 		a.t.Error(shouldBeEqual(a.actual, expected))
 	}

assert/error_messages.go

@@ -200,3 +200,7 @@ func shouldBeDefined(actual types.Assertable) string {
 func shouldNotBeDefined(actual types.Assertable) string {
 	return fmt.Sprintf("assertion failed: expected value of = %+v, to be un-defined but it was", actual.Value())
 }
+
+func shouldContainUniqueElements(actual types.Assertable) string {
+	return fmt.Sprintf("assertion failed: expected value of = %+v, to contain unique elements but it doesn't", actual.Value())
+}

assert/slice.go

@@ -106,3 +106,12 @@ func (a AssertableSlice) DoesNotContain(elements interface{}) AssertableSlice {
 	}
 	return a
 }
+
+// HasUniqueElements asserts if the assertable string slice does not contain the given element
+// It errors the test if it contains it/them.
+func (a AssertableSlice) HasUniqueElements() AssertableSlice {
+	if !(a.actual.HasUniqueElements()) {
+		a.t.Error(shouldContainUniqueElements(a.actual))
+	}
+	return a
+}

assert/slice_test.go

@@ -329,3 +329,34 @@ func TestAssertableSlice_DoesNotContain(t *testing.T) {
 		})
 	}
 }
+
+func TestAssertableSlice_HasUniqueElements(t *testing.T) {
+	tests := []struct {
+		name       string
+		actual     []string
+		shouldFail bool
+	}{
+		{
+			name:       "should not fail if slice has unique elements",
+			actual:     []string{"element", "element2", "element3"},
+			shouldFail: false,
+		},
+		{
+			name:       "should fail if slice has unique elements",
+			actual:     []string{"element", "element", "element3"},
+			shouldFail: true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			test := &testing.T{}
+			ThatSlice(test, tt.actual).HasUniqueElements()
+			ThatBool(t, test.Failed()).IsEqualTo(tt.shouldFail)
+		})
+	}
+	test := &testing.T{}
+	ThatSlice(test, []int{1, 2, 3}).HasUniqueElements()
+	ThatBool(t, test.Failed()).IsEqualTo(false)
+	ThatSlice(test, []int{1, 1, 3}).HasUniqueElements()
+	ThatBool(t, test.Failed()).IsEqualTo(true)
+}

internal/pkg/values/slice_value.go

@@ -83,6 +83,23 @@ func (s SliceValue) ContainsOnly(elements interface{}) bool {
 	return s.Contains(elements) && s.HasSize(reflect.ValueOf(elements).Len())
 }
 
+// HasUniqueElements returns true if the slice contains only unique elements else false.
+func (s SliceValue) HasUniqueElements() bool {
+	if !IsSlice(s.Value()) {
+		return false
+	}
+	sliceValue := reflect.ValueOf(s.value)
+	elements := map[interface{}]bool{}
+
+	for i := 0; i < sliceValue.Len(); i++ {
+		if _, ok := elements[sliceValue.Index(i).Interface()]; ok {
+			return false
+		}
+		elements[sliceValue.Index(i).Interface()] = true
+	}
+	return true
+}
+
 // Value returns the actual value of the structure.
 func (s SliceValue) Value() interface{} {
 	return s.value

types/types.go

@@ -34,6 +34,7 @@ type Containable interface {
 	Contains(elements interface{}) bool
 	ContainsOnly(elements interface{}) bool
 	DoesNotContain(elements interface{}) bool
+	HasUniqueElements() bool
 	Sizeable
 }