Decouple unit test code from business code (#17623)

modules/unittestbridge/unittestbridge.go

@@ -0,0 +1,46 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package unittestbridge
+
+// Usage: generally, non-unit-test code shouldn't depend on unit test code.
+// However, we have some code like models.CheckConsistencyFor, which need to do some unit test works.
+// Now we can not decouple models.CheckConsistencyFor from unit test code easily (cycle-import reasons).
+// So we introduce this `unit test bridge`:
+// * When a release binary is built, no testing/assert framework would be compiled into the binary, and CheckConsistencyFor won't run unit test related code
+// * When a unit test binary is built, the unit test code will init this bridge, then CheckConsistencyFor can run unit test related code
+//
+// Tester/Assert are intermediate interfaces, they should NOT be used in new code.
+// One day, if CheckConsistencyFor is clean enough, we can remove these intermediate interfaces.
+
+// Tester is the same as TestingT in "stretchr/testify/assert"
+// Tester can be used in non-unit-test code (ex: models.CheckConsistencyFor), it is used to isolate dependencies
+type Tester interface {
+	Errorf(format string, args ...interface{})
+}
+
+// Asserter can be used in non-unit-test code (ex: models.CheckConsistencyFor), it is used to isolate dependencies
+type Asserter interface {
+	Tester
+	NoError(err error, msgAndArgs ...interface{}) bool
+	EqualValues(expected, actual interface{}, msgAndArgs ...interface{}) bool
+	Equal(expected, actual interface{}, msgAndArgs ...interface{}) bool
+	True(value bool, msgAndArgs ...interface{}) bool
+	False(value bool, msgAndArgs ...interface{}) bool
+}
+
+var newAsserterFunc func(t Tester) Asserter
+
+// NewAsserter returns a new asserter, only works in unit test
+func NewAsserter(t Tester) Asserter {
+	if newAsserterFunc == nil {
+		panic("the newAsserterFunc is not set. you can only use assert in unit test.")
+	}
+	return newAsserterFunc(t)
+}
+
+// SetNewAsserterFunc in unit test, the asserter must be set first
+func SetNewAsserterFunc(f func(t Tester) Asserter) {
+	newAsserterFunc = f
+}