From 711d39eb10d52f59f008d81d8245e3574beb94c6 Mon Sep 17 00:00:00 2001
From: magicgoose <magicgoose@users.noreply.github.com>
Date: Mon, 23 Nov 2020 04:37:31 -0800
Subject: [PATCH] README: Better explanation of Return Value Provider Functions

---
 README.md | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index f5e9086ff..a4b1cd23f 100644
--- a/README.md
+++ b/README.md
@@ -222,7 +222,31 @@ Mock.On("passthrough", mock.AnythingOfType("context.Context"), mock.AnythingOfTy
 
 #### Requirements
 
-`Return` must be passed the same argument count and types as expected by the interface. If the return argument signature of `passthrough` in the above example was instead `(string, error)` in the interface, `Return` would also need a second argument to define the error value.
+`Return` must be passed the same argument count and types as expected by the interface. Then, for each of the return values of the mocked function, `Return` needs a function which takes the same arguments as the mocked function, and returns one of the return values. For example, if the return argument signature of `passthrough` in the above example was instead `(string, error)` in the interface, `Return` would also need a second function argument to define the error value:
+
+```go
+type Proxy interface {
+  passthrough(ctx context.Context, s string) (string, error)
+}
+```
+
+```go
+Mock.On("passthrough", mock.AnythingOfType("context.Context"), mock.AnythingOfType("string")).Return(
+	func(ctx context.Context, s string) string {
+		return s
+	},
+	func(ctx context.Context, s string) error {
+		return nil
+	})
+```
+
+Note that the following is incorrect (you can't return all the return values with one function):
+```go
+Mock.On("passthrough", mock.AnythingOfType("context.Context"), mock.AnythingOfType("string")).Return(
+	func(ctx context.Context, s string) (string, error) {
+		return s, nil
+	})
+```
 
 If any return argument is missing, `github.com/stretchr/testify/mock.Arguments.Get` will emit a panic.