mock

Documentation

Overview

Package mock provides a system by which it is possible to mock your objects and verify calls are happening as expected.

Example Usage

The mock package provides an object, Mock, that tracks activity on another object. It is usually embedded into a test object as shown below:

type MyTestObject struct {
  // add a Mock object instance
  mock.Mock

  // other fields go here as normal
}

When implementing the methods of an interface, you wire your functions up to call the Mock.Called(args...) method, and return the appropriate values.

For example, to mock a method that saves the name and age of a person and returns the year of their birth or an error, you might write this:

func (o *MyTestObject) SavePersonDetails(firstname, lastname string, age int) (int, error) {
  args := o.Called(firstname, lastname, age)
  return args.Int(0), args.Error(1)
}

The Int, Error and Bool methods are examples of strongly typed getters that take the argument index position. Given this argument list:

(12, true, "Something")

You could read them out strongly typed like this:

args.Int(0)
args.Bool(1)
args.String(2)

For objects of your own type, use the generic Arguments.Get(index) method and make a type assertion:

return args.Get(0).(*MyObject), args.Get(1).(*AnotherObjectOfMine)

This may cause a panic if the object you are getting is nil (the type assertion will fail), in those cases you should check for nil first.

Index

• Constants
• func AssertExpectationsForObjects(t TestingT, testObjects ...interface{}) bool
• func MatchedBy(fn interface{}) argumentMatcher
• type AnythingOfTypeArgument
  • func AnythingOfType(t string) AnythingOfTypeArgument
• type Arguments
  • func (args Arguments) Assert(t TestingT, objects ...interface{}) bool
  • func (args Arguments) Bool(index int) bool
  • func (args Arguments) Diff(objects []interface{}) (string, int)
  • func (args Arguments) Error(index int) error
  • func (args Arguments) Get(index int) interface{}
  • func (args Arguments) Int(index int) int
  • func (args Arguments) Is(objects ...interface{}) bool
  • func (args Arguments) String(indexOrNil ...int) string
• type Call
  • func (c *Call) After(d time.Duration) *Call
  • func (c *Call) Maybe() *Call
  • func (c *Call) On(methodName string, arguments ...interface{}) *Call
  • func (c *Call) Once() *Call
  • func (c *Call) Panic(msg string) *Call
  • func (c *Call) Return(returnArguments ...interface{}) *Call
  • func (c *Call) Run(fn func(args Arguments)) *Call
  • func (c *Call) Times(i int) *Call
  • func (c *Call) Twice() *Call
  • func (c *Call) WaitUntil(w <-chan time.Time) *Call
• type IsTypeArgument
  • func IsType(t interface{}) *IsTypeArgument
• type Mock
  • func (m *Mock) AssertCalled(t TestingT, methodName string, arguments ...interface{}) bool
  • func (m *Mock) AssertCalledAt(t TestingT, callIndex int, methodName string, arguments ...interface{}) bool
  • func (m *Mock) AssertExpectations(t TestingT) bool
  • func (m *Mock) AssertNotCalled(t TestingT, methodName string, arguments ...interface{}) bool
  • func (m *Mock) AssertNumberOfCalls(t TestingT, methodName string, expectedCalls int) bool
  • func (m *Mock) Called(arguments ...interface{}) Arguments
  • func (m *Mock) IsMethodCallable(t TestingT, methodName string, arguments ...interface{}) bool
  • func (m *Mock) MethodCalled(methodName string, arguments ...interface{}) Arguments
  • func (m *Mock) On(methodName string, arguments ...interface{}) *Call
  • func (m *Mock) Test(t TestingT)
  • func (m *Mock) TestData() objx.Map
• type TestingT

Constants

const (
	// Anything is used in Diff and Assert when the argument being tested
	// shouldn't be taken into consideration.
	Anything = "mock.Anything"
)

Functions

func AssertExpectationsForObjects

func AssertExpectationsForObjects(t TestingT, testObjects ...interface{}) bool

AssertExpectationsForObjects asserts that everything specified with On and Return of the specified objects was in fact called as expected.

Calls may have occurred in any order.

func MatchedBy

func MatchedBy(fn interface{}) argumentMatcher

MatchedBy can be used to match a mock call based on only certain properties from a complex struct or some calculation. It takes a function that will be evaluated with the called argument and will return true when there's a match and false otherwise.

Example: m.On("Do", MatchedBy(func(req *http.Request) bool { return req.Host == "example.com" }))

|fn|, must be a function accepting a single argument (of the expected type) which returns a bool. If |fn| doesn't match the required signature, MatchedBy() panics.

Types

type AnythingOfTypeArgument

type AnythingOfTypeArgument string

AnythingOfTypeArgument is a string that contains the type of an argument for use when type checking. Used in Diff and Assert.

func AnythingOfType

func AnythingOfType(t string) AnythingOfTypeArgument

AnythingOfType returns an AnythingOfTypeArgument object containing the name of the type to check for. Used in Diff and Assert.

For example:

Assert(t, AnythingOfType("string"), AnythingOfType("int"))

type Arguments

type Arguments []interface{}

Arguments holds an array of method arguments or return values.

func (Arguments) Assert

func (args Arguments) Assert(t TestingT, objects ...interface{}) bool

Assert compares the arguments with the specified objects and fails if they do not exactly match.

func (Arguments) Bool

func (args Arguments) Bool(index int) bool

Bool gets the argument at the specified index. Panics if there is no argument, or if the argument is of the wrong type.

func (Arguments) Diff

func (args Arguments) Diff(objects []interface{}) (string, int)

Diff gets a string describing the differences between the arguments and the specified objects.

Returns the diff string and number of differences found.

func (Arguments) Error

func (args Arguments) Error(index int) error

Error gets the argument at the specified index. Panics if there is no argument, or if the argument is of the wrong type.

func (Arguments) Get

func (args Arguments) Get(index int) interface{}

Get Returns the argument at the specified index.

func (Arguments) Int

func (args Arguments) Int(index int) int

Int gets the argument at the specified index. Panics if there is no argument, or if the argument is of the wrong type.

func (Arguments) Is

func (args Arguments) Is(objects ...interface{}) bool

Is gets whether the objects match the arguments specified.

func (Arguments) String

func (args Arguments) String(indexOrNil ...int) string

String gets the argument at the specified index. Panics if there is no argument, or if the argument is of the wrong type.

If no index is provided, String() returns a complete string representation of the arguments.

type Call

type Call struct {
	Parent *Mock

	// The name of the method that was or will be called.
	Method string

	// Holds the arguments of the method.
	Arguments Arguments

	// Holds the arguments that should be returned when
	// this method is called.
	ReturnArguments Arguments

	// The number of times to return the return arguments when setting
	// expectations. 0 means to always return the value.
	Repeatability int

	// Holds a channel that will be used to block the Return until it either
	// receives a message or is closed. nil means it returns immediately.
	WaitFor <-chan time.Time

	// Holds a handler used to manipulate arguments content that are passed by
	// reference. It's useful when mocking methods such as unmarshalers or
	// decoders.
	RunFn func(Arguments)

	// PanicMsg holds msg to be used to mock panic on the function call
	//  if the PanicMsg is set to a non nil string the function call will panic
	// irrespective of other settings
	PanicMsg *string
	// contains filtered or unexported fields
}

Call represents a method call and is used for setting expectations, as well as recording activity.

func (*Call) After

func (c *Call) After(d time.Duration) *Call

After sets how long to block until the call returns

Mock.On("MyMethod", arg1, arg2).After(time.Second)

func (*Call) Maybe

func (c *Call) Maybe() *Call

Maybe allows the method call to be optional. Not calling an optional method will not cause an error while asserting expectations

func (*Call) On

func (c *Call) On(methodName string, arguments ...interface{}) *Call

On chains a new expectation description onto the mocked interface. This allows syntax like.

Mock.
   On("MyMethod", 1).Return(nil).
   On("MyOtherMethod", 'a', 'b', 'c').Return(errors.New("Some Error"))

func (*Call) Once

func (c *Call) Once() *Call

Once indicates that that the mock should only return the value once.

Mock.On("MyMethod", arg1, arg2).Return(returnArg1, returnArg2).Once()

func (*Call) Panic

func (c *Call) Panic(msg string) *Call

Panic specifies if the functon call should fail and the panic message

Mock.On("DoSomething").Panic("test panic")

func (*Call) Return

func (c *Call) Return(returnArguments ...interface{}) *Call

Return specifies the return arguments for the expectation.

Mock.On("DoSomething").Return(errors.New("failed"))

func (*Call) Run

func (c *Call) Run(fn func(args Arguments)) *Call

Run sets a handler to be called before returning. It can be used when mocking a method (such as an unmarshaler) that takes a pointer to a struct and sets properties in such struct

Mock.On("Unmarshal", AnythingOfType("*map[string]interface{}")).Return().Run(func(args Arguments) {
	arg := args.Get(0).(*map[string]interface{})
	arg["foo"] = "bar"
})

func (*Call) Times

func (c *Call) Times(i int) *Call

Times indicates that that the mock should only return the indicated number of times.

Mock.On("MyMethod", arg1, arg2).Return(returnArg1, returnArg2).Times(5)

func (*Call) Twice

func (c *Call) Twice() *Call

Twice indicates that that the mock should only return the value twice.

Mock.On("MyMethod", arg1, arg2).Return(returnArg1, returnArg2).Twice()

func (*Call) WaitUntil

func (c *Call) WaitUntil(w <-chan time.Time) *Call

WaitUntil sets the channel that will block the mock's return until its closed or a message is received.

Mock.On("MyMethod", arg1, arg2).WaitUntil(time.After(time.Second))

type IsTypeArgument

type IsTypeArgument struct {
	// contains filtered or unexported fields
}

IsTypeArgument is a struct that contains the type of an argument for use when type checking. This is an alternative to AnythingOfType. Used in Diff and Assert.

func IsType

func IsType(t interface{}) *IsTypeArgument

IsType returns an IsTypeArgument object containing the type to check for. You can provide a zero-value of the type to check. This is an alternative to AnythingOfType. Used in Diff and Assert.

For example: Assert(t, IsType(""), IsType(0))

type Mock

type Mock struct {
	// Represents the calls that are expected of
	// an object.
	ExpectedCalls []*Call

	// Holds the calls that were made to this mocked object.
	Calls []Call
	// contains filtered or unexported fields
}

Mock is the workhorse used to track activity on another object. For an example of its usage, refer to the "Example Usage" section at the top of this document.

func (*Mock) AssertCalled

func (m *Mock) AssertCalled(t TestingT, methodName string, arguments ...interface{}) bool

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 (*Mock) AssertCalledAt

func (m *Mock) AssertCalledAt(t TestingT, callIndex int, methodName string, arguments ...interface{}) bool

func (*Mock) AssertExpectations

func (m *Mock) AssertExpectations(t TestingT) bool

AssertExpectations asserts that everything specified with On and Return was in fact called as expected. Calls may have occurred in any order.

func (*Mock) AssertNotCalled

func (m *Mock) AssertNotCalled(t TestingT, methodName string, arguments ...interface{}) bool

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 (*Mock) AssertNumberOfCalls

func (m *Mock) AssertNumberOfCalls(t TestingT, methodName string, expectedCalls int) bool

AssertNumberOfCalls asserts that the method was called expectedCalls times.

func (*Mock) Called

func (m *Mock) Called(arguments ...interface{}) Arguments

Called tells the mock object that a method has been called, and gets an array of arguments to return. Panics if the call is unexpected (i.e. not preceded by appropriate .On .Return() calls) If Call.WaitFor is set, blocks until the channel is closed or receives a message.

func (*Mock) IsMethodCallable

func (m *Mock) IsMethodCallable(t TestingT, methodName string, arguments ...interface{}) bool

IsMethodCallable checking that the method can be called If the method was called more than `Repeatability` return false

func (*Mock) MethodCalled

func (m *Mock) MethodCalled(methodName string, arguments ...interface{}) Arguments

MethodCalled tells the mock object that the given method has been called, and gets an array of arguments to return. Panics if the call is unexpected (i.e. not preceded by appropriate .On .Return() calls) If Call.WaitFor is set, blocks until the channel is closed or receives a message.

func (*Mock) On

func (m *Mock) On(methodName string, arguments ...interface{}) *Call

On starts a description of an expectation of the specified method being called.

Mock.On("MyMethod", arg1, arg2)

func (*Mock) Test

func (m *Mock) Test(t TestingT)

Test sets the test struct variable of the mock object

func (*Mock) TestData

func (m *Mock) TestData() objx.Map

TestData holds any data that might be useful for testing. Testify ignores this data completely allowing you to do whatever you like with it.

type TestingT

type TestingT interface {
	Logf(format string, args ...interface{})
	Errorf(format string, args ...interface{})
	FailNow()
}

TestingT is an interface wrapper around *testing.T