From 943285313bf60fddc1e3f9de81c28ddb48c15b67 Mon Sep 17 00:00:00 2001
From: James Batt <getjamesbatt@gmail.com>
Date: Sat, 16 Apr 2022 17:30:58 +1000
Subject: [PATCH] nil handling for Call() (#40)

* nil handling for Call()

* added a testcase
---
 container.go      |  3 +++
 container_test.go | 14 ++++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/container.go b/container.go
index c3537a0..6f6ac44 100644
--- a/container.go
+++ b/container.go
@@ -150,6 +150,9 @@ func (c Container) Call(function interface{}) error {
 	if len(result) == 0 {
 		return nil
 	} else if len(result) == 1 && result[0].CanInterface() {
+		if result[0].IsNil() {
+			return nil
+		}
 		if err, ok := result[0].Interface().(error); ok {
 			return err
 		}
diff --git a/container_test.go b/container_test.go
index 8d968ca..448f1da 100644
--- a/container_test.go
+++ b/container_test.go
@@ -223,6 +223,20 @@ func TestContainer_Call_With_A_Returning_Error(t *testing.T) {
 	assert.EqualError(t, err, "app: some context error")
 }
 
+func TestContainer_Call_With_A_Returning_Nil_Error(t *testing.T) {
+	instance.Reset()
+
+	err := instance.Singleton(func() Shape {
+		return &Circle{}
+	})
+	assert.NoError(t, err)
+
+	err = instance.Call(func(s Shape) error {
+		return nil
+	})
+	assert.Nil(t, err)
+}
+
 func TestContainer_Call_With_Invalid_Signature(t *testing.T) {
 	instance.Reset()