mock

Documentation

Overview

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.Mock.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
• 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
• type Mock
  • func (m *Mock) AssertCalled(t TestingT, 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) On(methodName string, arguments ...interface{}) *Mock
  • func (m *Mock) Once()
  • func (m *Mock) Return(returnArguments ...interface{}) *Mock
  • func (m *Mock) TestData() objx.Map
  • func (m *Mock) Times(i int)
  • func (m *Mock) Twice()
• type TestingT

Constants

const (
	// The "any" argument.  Used in Diff and Assert when
	// the argument being tested shouldn't be taken into consideration.
	Anything string = "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.

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 {

	// 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
}

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

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.

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.

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 preceeded by appropriate .On .Return() calls)

func (*Mock) On

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

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

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

func (*Mock) Once

func (m *Mock) Once()

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

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

func (*Mock) Return

func (m *Mock) Return(returnArguments ...interface{}) *Mock

Return finishes a description of an expectation of the method (and arguments) specified in the most recent On method call.

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

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.

func (*Mock) Times

func (m *Mock) Times(i int)

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 (*Mock) Twice

func (m *Mock) Twice()

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

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

type TestingT

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

TestingT is an interface wrapper around *testing.T