lesiw.io/moxie: Generate mocks with proxy functions

Go has a convenient feature called embedding. Method calls are transparently passed through to embedded types.

moxie generates proxy methods that are only added during go test.

Usage

Add this line to your code, where T is the type you want to instrument, and E is the embedded type whose functions you want to intercept.

//go:generate go run lesiw.io/moxie@latest T
type T struct {
    E
}

Then run go generate.

Functions

moxie makes the following methods on T available at test time.

Instance methods

(*T)._Func_Stub()      // when called, return zero values.
(*T)._Func_Return(...) // when called, return these values.

(*T)._Func_Do(func() {...}) // when called, run this instead.
                            // calling this with nil will un-mock the function.

(*T)._Func_Calls() []_T_Func_Call // return calls to Func.

Mocks queue. For example, mocking with (*T)._Func_Return twice will return the first set of values the next time the function is called, then return the second set of values in subsequent calls.

Global methods

new(T)._Func_StubAll(*testing.T)         // when called, return zero values.
new(T)._Func_ReturnAll(*testing.T, ...)  // when called, return these values.

new(T)._Func_DoAll(*testing.T, func() {...}) // when called, run this instead.
                                             // calling this with nil
                                             // will un-mock the function.

new(T)._Func_AllCalls() []_T_Func_Call // return calls to Func.
new(T)._Func_BubbleCalls(*testing.T)   // clear calls before and after test.

As above, mocks queue.

These methods may be easier to use in some cases, as they operate on all T types. This can be helpful in situations where injecting a mock value into the code under test may be difficult to do. Note, however, that this makes them unsafe for use with t.Parallel().

Methods that accept a *testing.T will clean up mocks at the end of their corresponding test or subtest.

Tests using AllCalls() should also call new(T)._Func_BubbleCalls(t), otherwise AllCalls() may also contain calls from other tests.