Fix race condition on mock package's Called

Closes #442

mock/mock.go

@@ -214,8 +214,6 @@ func (m *Mock) On(methodName string, arguments ...interface{}) *Call {
 // */
 
 func (m *Mock) findExpectedCall(method string, arguments ...interface{}) (int, *Call) {
-	m.mutex.Lock()
-	defer m.mutex.Unlock()
 	for i, call := range m.ExpectedCalls {
 		if call.Method == method && call.Repeatability > -1 {
 
@@ -288,6 +286,7 @@ func (m *Mock) Called(arguments ...interface{}) Arguments {
 	parts := strings.Split(functionPath, ".")
 	functionName := parts[len(parts)-1]
 
+	m.mutex.Lock()
 	found, call := m.findExpectedCall(functionName, arguments...)
 
 	if found < 0 {
@@ -299,31 +298,29 @@ func (m *Mock) Called(arguments ...interface{}) Arguments {
 		//   c) the developer has forgotten to add an accompanying On...Return pair.
 
 		closestFound, closestCall := m.findClosestCall(functionName, arguments...)
+		m.mutex.Unlock()
 
 		if closestFound {
 			panic(fmt.Sprintf("\n\nmock: Unexpected Method Call\n-----------------------------\n\n%s\n\nThe closest call I have is: \n\n%s\n\n%s\n", callString(functionName, arguments, true), callString(functionName, closestCall.Arguments, true), diffArguments(arguments, closestCall.Arguments)))
 		} else {
 			panic(fmt.Sprintf("\nassert: mock: I don't know what to return because the method call was unexpected.\n\tEither do Mock.On(\"%s\").Return(...) first, or remove the %s() call.\n\tThis method was unexpected:\n\t\t%s\n\tat: %s", functionName, functionName, callString(functionName, arguments, true), assert.CallerInfo()))
 		}
-	} else {
+	}
-		m.mutex.Lock()
-		switch {
-		case call.Repeatability == 1:
-			call.Repeatability = -1
-			call.totalCalls++
 
-		case call.Repeatability > 1:
+	switch {
-			call.Repeatability--
+	case call.Repeatability == 1:
-			call.totalCalls++
+		call.Repeatability = -1
+		call.totalCalls++
 
-		case call.Repeatability == 0:
+	case call.Repeatability > 1:
-			call.totalCalls++
+		call.Repeatability--
-		}
+		call.totalCalls++
-		m.mutex.Unlock()
+
+	case call.Repeatability == 0:
+		call.totalCalls++
 	}
 
 	// add the call
-	m.mutex.Lock()
 	m.Calls = append(m.Calls, *newCall(m, functionName, arguments...))
 	m.mutex.Unlock()
 
@@ -368,6 +365,8 @@ func AssertExpectationsForObjects(t TestingT, testObjects ...interface{}) bool {
 // AssertExpectations asserts that everything specified with On and Return was
 // in fact called as expected.  Calls may have occurred in any order.
 func (m *Mock) AssertExpectations(t TestingT) bool {
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
 	var somethingMissing bool
 	var failedExpectations int
 
@@ -379,14 +378,12 @@ func (m *Mock) AssertExpectations(t TestingT) bool {
 			failedExpectations++
 			t.Logf("\u274C\t%s(%s)", expectedCall.Method, expectedCall.Arguments.String())
 		} else {
-			m.mutex.Lock()
 			if expectedCall.Repeatability > 0 {
 				somethingMissing = true
 				failedExpectations++
 			} else {
 				t.Logf("\u2705\t%s(%s)", expectedCall.Method, expectedCall.Arguments.String())
 			}
-			m.mutex.Unlock()
 		}
 	}
 
@@ -399,6 +396,8 @@ func (m *Mock) AssertExpectations(t TestingT) bool {
 
 // AssertNumberOfCalls asserts that the method was called expectedCalls times.
 func (m *Mock) AssertNumberOfCalls(t TestingT, methodName string, expectedCalls int) bool {
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
 	var actualCalls int
 	for _, call := range m.calls() {
 		if call.Method == methodName {
@@ -411,6 +410,8 @@ func (m *Mock) AssertNumberOfCalls(t TestingT, methodName string, expectedCalls
 // AssertCalled asserts that the method was called.
 // It can produce a false result when an argument is a pointer type and the underlying value changed after calling the mocked method.
 func (m *Mock) AssertCalled(t TestingT, methodName string, arguments ...interface{}) bool {
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
 	if !assert.True(t, m.methodWasCalled(methodName, arguments), fmt.Sprintf("The \"%s\" method should have been called with %d argument(s), but was not.", methodName, len(arguments))) {
 		t.Logf("%v", m.expectedCalls())
 		return false
@@ -421,6 +422,8 @@ func (m *Mock) AssertCalled(t TestingT, methodName string, arguments ...interfac
 // AssertNotCalled asserts that the method was not called.
 // It can produce a false result when an argument is a pointer type and the underlying value changed after calling the mocked method.
 func (m *Mock) AssertNotCalled(t TestingT, methodName string, arguments ...interface{}) bool {
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
 	if !assert.False(t, m.methodWasCalled(methodName, arguments), fmt.Sprintf("The \"%s\" method was called with %d argument(s), but should NOT have been.", methodName, len(arguments))) {
 		t.Logf("%v", m.expectedCalls())
 		return false
@@ -446,14 +449,10 @@ func (m *Mock) methodWasCalled(methodName string, expected []interface{}) bool {
 }
 
 func (m *Mock) expectedCalls() []*Call {
-	m.mutex.Lock()
-	defer m.mutex.Unlock()
 	return append([]*Call{}, m.ExpectedCalls...)
 }
 
 func (m *Mock) calls() []Call {
-	m.mutex.Lock()
-	defer m.mutex.Unlock()
 	return append([]Call{}, m.Calls...)
 }