src/gobang.go: Add ExitIf()

2 files changed, 41 insertions, 0 deletions

diff --git a/src/gobang.go b/src/gobang.go
index 3da691e..8777247 100644
--- a/src/gobang.go
+++ b/src/gobang.go
@@ -66,6 +66,7 @@ var (
 
 	testOutput io.Writer = os.Stderr
 	testExitFn  = os.Exit
+	exitFn      = os.Exit
 	randomReader = rand.Reader
 
 	SourceInfoSkip = 3
@@ -117,6 +118,12 @@ func Filter[A any](fn func(A) bool, coll []A) []A {
 	return out
 }
 
+func ExitIf(rc int) {
+	if rc != 0 {
+		exitFn(rc)
+	}
+}
+
 func PanicIf(err error) {
 	if err != nil {
 		panic(err)
diff --git a/tests/gobang.go b/tests/gobang.go
index 16ff0fe..fe47086 100644
--- a/tests/gobang.go
+++ b/tests/gobang.go
@@ -142,6 +142,39 @@ func test_Filter() {
 	})
 }
 
+func test_ExitIf() {
+	TestStart("ExitIf()")
+
+	n := -1
+	myExitFn := func(val int) {
+		n = val
+	}
+
+	Testing("noop when value is 0", func() {
+		savedExitFn := exitFn
+		exitFn = myExitFn
+
+		ExitIf(0)
+
+		exitFn = savedExitFn
+
+		TAssertEqual(n, -1)
+	})
+
+	Testing("exitFn() is called otherwise", func() {
+		savedExitFn := exitFn
+		exitFn = myExitFn
+
+		ExitIf(1)
+		TAssertEqual(n, 1)
+
+		ExitIf(123)
+		TAssertEqual(n, 123)
+
+		exitFn = savedExitFn
+	})
+}
+
 func test_PanicIf() {
 	TestStart("PanicIf()")
 
@@ -1528,6 +1561,7 @@ func MainTest() {
 	test_MapIndexed()
 	test_Map()
 	test_Filter()
+	test_ExitIf()
 	test_PanicIf()
 	test_Must()
 	test_Clamp()