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// Copyright 2010 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Package gomock is a mock framework for Go.
//
// Standard usage:
// (1) Define an interface that you wish to mock.
// type MyInterface interface {
// SomeMethod(x int64, y string)
// }
// (2) Use mockgen to generate a mock from the interface.
// (3) Use the mock in a test:
// func TestMyThing(t *testing.T) {
// mockCtrl := gomock.NewController(t)
// defer mockCtrl.Finish()
//
// mockObj := something.NewMockMyInterface(mockCtrl)
// mockObj.EXPECT().SomeMethod(4, "blah")
// // pass mockObj to a real object and play with it.
// }
//
// By default, expected calls are not enforced to run in any particular order.
// Call order dependency can be enforced by use of InOrder and/or Call.After.
// Call.After can create more varied call order dependencies, but InOrder is
// often more convenient.
//
// The following examples create equivalent call order dependencies.
//
// Example of using Call.After to chain expected call order:
//
// firstCall := mockObj.EXPECT().SomeMethod(1, "first")
// secondCall := mockObj.EXPECT().SomeMethod(2, "second").After(firstCall)
// mockObj.EXPECT().SomeMethod(3, "third").After(secondCall)
//
// Example of using InOrder to declare expected call order:
//
// gomock.InOrder(
// mockObj.EXPECT().SomeMethod(1, "first"),
// mockObj.EXPECT().SomeMethod(2, "second"),
// mockObj.EXPECT().SomeMethod(3, "third"),
// )
//
// TODO:
// - Handle different argument/return types (e.g. ..., chan, map, interface).
package gomock
import (
"context"
"fmt"
"reflect"
"runtime"
"sync"
)
// A TestReporter is something that can be used to report test failures. It
// is satisfied by the standard library's *testing.T.
type TestReporter interface {
Errorf(format string, args ...interface{})
Fatalf(format string, args ...interface{})
}
// TestHelper is a TestReporter that has the Helper method. It is satisfied
// by the standard library's *testing.T.
type TestHelper interface {
TestReporter
Helper()
}
// A Controller represents the top-level control of a mock ecosystem. It
// defines the scope and lifetime of mock objects, as well as their
// expectations. It is safe to call Controller's methods from multiple
// goroutines. Each test should create a new Controller and invoke Finish via
// defer.
//
// func TestFoo(t *testing.T) {
// ctrl := gomock.NewController(t)
// defer ctrl.Finish()
// // ..
// }
//
// func TestBar(t *testing.T) {
// t.Run("Sub-Test-1", st) {
// ctrl := gomock.NewController(st)
// defer ctrl.Finish()
// // ..
// })
// t.Run("Sub-Test-2", st) {
// ctrl := gomock.NewController(st)
// defer ctrl.Finish()
// // ..
// })
// })
type Controller struct {
// T should only be called within a generated mock. It is not intended to
// be used in user code and may be changed in future versions. T is the
// TestReporter passed in when creating the Controller via NewController.
// If the TestReporter does not implement a TestHelper it will be wrapped
// with a nopTestHelper.
T TestHelper
mu sync.Mutex
expectedCalls *callSet
finished bool
}
// NewController returns a new Controller. It is the preferred way to create a
// Controller.
func NewController(t TestReporter) *Controller {
h, ok := t.(TestHelper)
if !ok {
h = nopTestHelper{t}
}
return &Controller{
T: h,
expectedCalls: newCallSet(),
}
}
type cancelReporter struct {
TestHelper
cancel func()
}
func (r *cancelReporter) Errorf(format string, args ...interface{}) {
r.TestHelper.Errorf(format, args...)
}
func (r *cancelReporter) Fatalf(format string, args ...interface{}) {
defer r.cancel()
r.TestHelper.Fatalf(format, args...)
}
// WithContext returns a new Controller and a Context, which is cancelled on any
// fatal failure.
func WithContext(ctx context.Context, t TestReporter) (*Controller, context.Context) {
h, ok := t.(TestHelper)
if !ok {
h = nopTestHelper{t}
}
ctx, cancel := context.WithCancel(ctx)
return NewController(&cancelReporter{h, cancel}), ctx
}
type nopTestHelper struct {
TestReporter
}
func (h nopTestHelper) Helper() {}
// RecordCall is called by a mock. It should not be called by user code.
func (ctrl *Controller) RecordCall(receiver interface{}, method string, args ...interface{}) *Call {
ctrl.T.Helper()
recv := reflect.ValueOf(receiver)
for i := 0; i < recv.Type().NumMethod(); i++ {
if recv.Type().Method(i).Name == method {
return ctrl.RecordCallWithMethodType(receiver, method, recv.Method(i).Type(), args...)
}
}
ctrl.T.Fatalf("gomock: failed finding method %s on %T", method, receiver)
panic("unreachable")
}
// RecordCallWithMethodType is called by a mock. It should not be called by user code.
func (ctrl *Controller) RecordCallWithMethodType(receiver interface{}, method string, methodType reflect.Type, args ...interface{}) *Call {
ctrl.T.Helper()
call := newCall(ctrl.T, receiver, method, methodType, args...)
ctrl.mu.Lock()
defer ctrl.mu.Unlock()
ctrl.expectedCalls.Add(call)
return call
}
// Call is called by a mock. It should not be called by user code.
func (ctrl *Controller) Call(receiver interface{}, method string, args ...interface{}) []interface{} {
ctrl.T.Helper()
// Nest this code so we can use defer to make sure the lock is released.
actions := func() []func([]interface{}) []interface{} {
ctrl.T.Helper()
ctrl.mu.Lock()
defer ctrl.mu.Unlock()
expected, err := ctrl.expectedCalls.FindMatch(receiver, method, args)
if err != nil {
origin := callerInfo(2)
ctrl.T.Fatalf("Unexpected call to %T.%v(%v) at %s because: %s", receiver, method, args, origin, err)
}
// Two things happen here:
// * the matching call no longer needs to check prerequite calls,
// * and the prerequite calls are no longer expected, so remove them.
preReqCalls := expected.dropPrereqs()
for _, preReqCall := range preReqCalls {
ctrl.expectedCalls.Remove(preReqCall)
}
actions := expected.call()
if expected.exhausted() {
ctrl.expectedCalls.Remove(expected)
}
return actions
}()
var rets []interface{}
for _, action := range actions {
if r := action(args); r != nil {
rets = r
}
}
return rets
}
// Finish checks to see if all the methods that were expected to be called
// were called. It should be invoked for each Controller. It is not idempotent
// and therefore can only be invoked once.
func (ctrl *Controller) Finish() {
ctrl.T.Helper()
ctrl.mu.Lock()
defer ctrl.mu.Unlock()
if ctrl.finished {
ctrl.T.Fatalf("Controller.Finish was called more than once. It has to be called exactly once.")
}
ctrl.finished = true
// If we're currently panicking, probably because this is a deferred call,
// pass through the panic.
if err := recover(); err != nil {
panic(err)
}
// Check that all remaining expected calls are satisfied.
failures := ctrl.expectedCalls.Failures()
for _, call := range failures {
ctrl.T.Errorf("missing call(s) to %v", call)
}
if len(failures) != 0 {
ctrl.T.Fatalf("aborting test due to missing call(s)")
}
}
func callerInfo(skip int) string {
if _, file, line, ok := runtime.Caller(skip + 1); ok {
return fmt.Sprintf("%s:%d", file, line)
}
return "unknown file"
}