README
¶
Fakery - Mock codegen for easy fakes in Go
Fake it 'til you make it!
- Focused on fakes, not assertions
- Making use of generics for type-safety
- Keeping the size of generated code small
- Producing clear output when a call is not matched
Usage
Generating mocks
The CLI is very hacked-together and subject to change. For now:
$ go install github.com/devnev/fakery/cmd/fakery@latest
# a specific interface
$ fakery -src src_file.go -name Iface -dst mock_iface.go
# all interfaces annotated with //fakery:unstable
$ fakery -src .
Using generated mocks
func TestDoThing(t *testing.T) {
mockIface := &Mock_IFace{}
On_Iface_DoThing(mockIface, fakery.Equal("hello"), fakery.ReturnNothing, fakery.Once())
// A *MockIface can be used anywhere an Iface is expected
var realIface Iface = mockIface
realIface.DoThing("hello")
}
func TestDoThingCallArgs(t *testing.T) {
mockIface := &Mock_IFace{}
var doThingArgs [][]any
On_Iface_DoThing(mockIface, fakery.Any[string](), fakery.ReturnNothing, fakery.AppendArgs(&doThingArgs))
runTest(mockIface)
// Use your preferred way of asserting, e.g. hand-rolled or testify assertions
assert.Equal(t, [][]any{{"hello"}, {"world"}}, doThingArgs)
}
Example failure
Matcher 1 (/gopath/github.com/devnev/fakery/example/example_test.go:30)
Arg 0:
string(
- "hello",
+ "goodbye",
)
Matcher 2 (/gopath/github.com/devnev/fakery/example/example_test.go:31)
Times(2):
Called 2 times out of 2
--- FAIL: TestFakeryNoMatch (0.00s)
panic: no match for call to Get [recovered]
panic: no match for call to Get
goroutine 34 [running]:
testing.tRunner.func1.2({0x11d6b00, 0xc00010a790})
/usr/local/Cellar/go/1.19/libexec/src/testing/testing.go:1396 +0x24e
testing.tRunner.func1()
/usr/local/Cellar/go/1.19/libexec/src/testing/testing.go:1399 +0x39f
panic({0x11d6b00, 0xc00010a790})
/usr/local/Cellar/go/1.19/libexec/src/runtime/panic.go:884 +0x212
github.com/devnev/fakery/internal/backend.Called(0xc000112050?, {0x1213231, 0x3}, {0xc00010a640, 0x1, 0x1})
/gopath/github.com/devnev/fakery/internal/backend/mocking.go:64 +0x485
github.com/devnev/fakery/gendeps.Called(...)
/gopath/github.com/devnev/fakery/gendeps/mocking.go:18
github.com/devnev/fakery/example.(*Mock_ToBeMocked).Get(0xc000106e88, {0x1213c75, 0x7})
/gopath/github.com/devnev/fakery/example/example_mock.go:19 +0xcb
github.com/devnev/fakery/example.TestFakeryNoMatch(0xc000116820)
/gopath/github.com/devnev/fakery/example/example_test.go:36 +0x1a5
testing.tRunner(0xc000116820, 0x1222a00)
/usr/local/Cellar/go/1.19/libexec/src/testing/testing.go:1446 +0x10b
created by testing.(*T).Run
/usr/local/Cellar/go/1.19/libexec/src/testing/testing.go:1493 +0x35f
FAIL github.com/devnev/fakery/example 0.307s
FAIL
Extended usage & adaptation
The package provides utilities for matching arguments,
Equal(value)
Any()
returning values,
ReturningNothing()
Returning1(value)
Returning2(value1, value2)
//etc.
Returning1v(value1, value2)
recording calls,
Increment(&counter)
AppendArgs(&args)
and other controls,
Once()
Times(n)
WaitFor(ch)
Any of the above can be accomplished and extended with the parameters to the
On_* functions:
Arguments matchers
Argument matchers have the signature
func(int, ArgType) string
The first argument is the argument index - mainly for use in failure messages - the second is argument value. A non-empty return value indicates that the argument does not match, with the reason as the string value. The mock is locked against further calls to any method while the argument matchers are run.
Return handlers
Return value handlers have two possible signatures and two stages:
// with args
func(...ArgTypes...) (string, func() (...ReturnTypes...))
// or without args
func() (string, func() (...ReturnTypes...))
The first stage runs before the match is confirmed (while the mock is locked against further calls to any method), and may return a non-empty string to indicate that the match failed.
If the first stage returns an empty string, it must also return a function for the second stage. This stage runs when the call matching is complete and the lock is released. It must return the values for the matched call to return.
Documentation
¶
Index ¶
- func Any[T any]() func(int, T) string
- func Equal[T any](v T) func(int, T) string
- func Returning1[T any](a0 T) func() (string, func() T)
- func Returning1v[T0 any](a0 ...T0) func() (string, func() T0)
- func Returning2[T0 any, T1 any](a0 T0, a1 T1) func() (string, func() (T0, T1))
- func Returning3[T0 any, T1 any, T2 any](a0 T0, a1 T1, a2 T2) func() (string, func() (T0, T1, T2))
- func Returning4[T0 any, T1 any, T2 any, T3 any](a0 T0, a1 T1, a2 T2, a3 T3) func() (string, func() (T0, T1, T2, T3))
- func Returning5[T0 any, T1 any, T2 any, T3 any, T4 any](a0 T0, a1 T1, a2 T2, a3 T3, a4 T4) func() (string, func() (T0, T1, T2, T3, T4))
- func ReturningNothing() func() (string, func())
- func VarArgs[T any](matchers ...func(int, T) string) func(int, []T) string
- type Option
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func Returning1 ¶
Returning1 creates a return handler that always matches and returns one value.
func Returning1v ¶
Returning1v creates a return handler that returns one item in the sequence at a time and matches as long as their are items remaining.
func Returning2 ¶
Returning2 creates a return handler that always matches and returns two values.
func Returning3 ¶
Returning3 creates a return handler that always matches and returns three values.
func Returning4 ¶
func Returning4[T0 any, T1 any, T2 any, T3 any](a0 T0, a1 T1, a2 T2, a3 T3) func() (string, func() (T0, T1, T2, T3))
Returning4 creates a return handler that always matches and returns four values.
func Returning5 ¶
func Returning5[T0 any, T1 any, T2 any, T3 any, T4 any](a0 T0, a1 T1, a2 T2, a3 T3, a4 T4) func() (string, func() (T0, T1, T2, T3, T4))
Returning5 creates a return handler that always matches and returns five values.
func ReturningNothing ¶
func ReturningNothing() func() (string, func())
ReturningNothing creates a return handler that always matches and returns no values.
Types ¶
type Option ¶
func AppendArgs ¶
AppendArgs appends the arguments of a matched call to a slice of argument slices.
func Increment ¶
func Increment[T constraints.Integer](counter *T) Option
Increment increments the counter when an invocation matches.
Source Files
Directories