Q&D test to optimize assert.Zero even it's generics, good strategy

Author: lainio

assert/assert.go

@@ -899,11 +899,15 @@ func Less[T Number](val, want T, a ...any) {
 // are used to override the auto-generated assert violation message.
 func Zero[T Number](val T, a ...any) {
 	if val != 0 {
-		defMsg := fmt.Sprintf(assertionMsg+": got '%v', want (== '0')", val)
-		current().reportAssertionFault(defMsg, a)
+		doZero(val, a)
 	}
 }
 
+func doZero[T Number](val T, a []any) {
+	defMsg := fmt.Sprintf(assertionMsg+": got '%v', want (== '0')", val)
+	current().newReportAssertionFault(defMsg, a)
+}
+
 // NotZero asserts that the value != 0. If it is not it panics and builds a
 // violation message. Thanks to inlining, the performance penalty is equal to a
 // single 'if-statement' that is almost nothing.

assert/asserter.go

@@ -86,6 +86,36 @@ func (asserter asserter) reportAssertionFault(defaultMsg string, a []any) {
 	}
 }
 
+func (asserter asserter) newReportAssertionFault(defaultMsg string, a []any) {
+	if asserter.hasStackTrace() {
+		if asserter.isUnitTesting() {
+			// Note. that the assert in the test function is printed in
+			// reportPanic below
+			const stackLvl = 4 // amount of functions before we're here
+			debug.PrintStackForTest(os.Stderr, stackLvl)
+		} else {
+			// amount of functions before we're here, which is different
+			// between runtime (this) and test-run (above)
+			const stackLvl = 1
+			debug.PrintStack(stackLvl)
+		}
+	}
+	if asserter.hasCallerInfo() {
+		defaultMsg = asserter.newCallerInfo(defaultMsg)
+	}
+	if len(a) > 0 {
+		if format, ok := a[0].(string); ok {
+			allowDefMsg := !asserter.isErrorOnly() && defaultMsg != ""
+			f := x.Whom(allowDefMsg, defaultMsg+conCatErrStr+format, format)
+			asserter.reportPanic(fmt.Sprintf(f, a[1:]...))
+		} else {
+			asserter.reportPanic(fmt.Sprintln(append([]any{defaultMsg}, a...)))
+		}
+	} else {
+		asserter.reportPanic(defaultMsg)
+	}
+}
+
 func (asserter asserter) reportPanic(s string) {
 	if asserter.isUnitTesting() && asserter.hasCallerInfo() {
 		fmt.Fprintln(os.Stderr, officialTestOutputPrefix+s)
@@ -144,6 +174,24 @@ func (asserter asserter) callerInfo(msg string) (info string) {
 	return
 }
 
+func (asserter asserter) newCallerInfo(msg string) (info string) {
+	ourFmtStr := shortFmtStr
+	if asserter.hasFormattedCallerInfo() {
+		ourFmtStr = longFmtStr
+	}
+
+	const framesToSkip = 4 // how many fn calls there is before FuncName call
+	includePath := asserter.isUnitTesting()
+	funcName, filename, line, ok := str.FuncName(framesToSkip, includePath)
+	if ok {
+		info = fmt.Sprintf(ourFmtStr,
+			filename, line,
+			funcName, msg)
+	}
+
+	return
+}
+
 func (asserter asserter) isErrorOnly() bool {
 	return asserter == asserterToError
 }