pub interface ReaderWriter {
	read(mut buf []u8) ?int // from Reader
	write(buf []u8) ?int    // from Writer
}

interface Speaker {
	// first
	speak() string
	// between
	foo() string
	foo2() string
	// last
}

interface Baz {
	// first
	speak() string
	// comment
	// more between
	foo() string
	foo2() string
	// last
}

interface Bar {
	speak() string // after
	foo() string
	speak2() string // also after
	// and between
	foo2() string
}

interface TestsRunner {
mut:
	fn_passes     u64
	fn_fails      u64
	assert_passes u64
	assert_fails  u64
	test_fn_info  &TestFnMetaInfo // filled in by generated code, before .fn_start() is called.
	start(ntests int) // called before all tests, you can initialise private data here. ntests is the number of test functions in the _test.v file.
	finish()          // called after all tests are finished, you should free all the private data here.
	//
	fn_start() // called at the start of each test_ function
	fn_pass()  // called at the end of each test_ function, with no failed assertion
	fn_error(line_nr int, file string, mod string, fn_name string, errmsg string) // called only for `fn test_xyz() ? { return error('message') }`
	fn_fail() // called at the end of each test_ function, with a failed assertion, *or* returning an error
	//
	assert_pass(i &AssertMetaInfo) // called for each `assert true`
	assert_fail(i &AssertMetaInfo) // called for each `assert false`
}