fix for comparing kinds

Author: alexpantyukhin

assert/assertions.go

@@ -419,6 +419,17 @@ func NotNil(t TestingT, object interface{}, msgAndArgs ...interface{}) bool {
 	return Fail(t, "Expected value not to be nil.", msgAndArgs...)
 }
 
+// containsKind checks if a specified kind in the slice of kinds.
+func containsKind(kinds []reflect.Kind, kind reflect.Kind) bool {
+	for i := 0; i < len(kinds); i++ {
+		if kind == kinds[i] {
+			return true
+		}
+	}
+
+	return false
+}
+
 // isNil checks if a specified object is nil or not, without Failing.
 func isNil(object interface{}) bool {
 	if object == nil {
@@ -427,7 +438,14 @@ func isNil(object interface{}) bool {
 
 	value := reflect.ValueOf(object)
 	kind := value.Kind()
-	if kind >= reflect.Chan && kind <= reflect.Slice && value.IsNil() {
+	isNilableKind := containsKind(
+		[]reflect.Kind{
+			reflect.Chan, reflect.Func,
+			reflect.Interface, reflect.Map,
+			reflect.Ptr, reflect.Slice},
+		kind)
+
+	if isNilableKind && value.IsNil() {
 		return true
 	}