From 9e1bda590fbb412257c476e87fed7f6d903b8acf Mon Sep 17 00:00:00 2001
From: Anton Novojilov <andy@essentialkaos.com>
Date: Wed, 8 Mar 2023 13:07:55 +0300
Subject: [PATCH] Add NotPanics checker

---
 README.md   |  5 +++++
 checkers.go | 36 +++++++++++++++++++++++++++++++++++-
 2 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index d3dfec9..44a9371 100644
--- a/README.md
+++ b/README.md
@@ -265,6 +265,11 @@ c.Assert(func() { f(1, 2) }, PanicMatches, `open.*: no such file or directory`)
 c.Assert(func() { f(1, 2) }, Panics, &SomeErrorType{"BOOM"}).
 ```
 
+**`NotPanics`** — Checker verifies that calling the provided zero-argument function will not cause any panic.
+```golang
+c.Assert(func() { f(1, 2) }, NotPanics).
+```
+
 ### Selecting which tests to run
 
 `gocheck` can filter tests out based on the test name, the suite name, or both. To run tests selectively, provide the command line option `-check.f` when running go test. Note that this option is specific to gocheck, and won't affect `go test` itself.
diff --git a/checkers.go b/checkers.go
index 03f076c..a0c5168 100644
--- a/checkers.go
+++ b/checkers.go
@@ -424,7 +424,41 @@ func matches(value, regex interface{}) (result bool, error string) {
 }
 
 // -----------------------------------------------------------------------
-// Panics checker.
+// NotPanics checker.
+
+type notPanicsChecker struct {
+	*CheckerInfo
+}
+
+// The NotPanics checker verifies that calling the provided zero-argument
+// function will not cause any panic.
+//
+// For example:
+//
+//     c.Assert(func() { f(1, 2) }, NotPanics).
+//
+//
+var NotPanics Checker = &notPanicsChecker{
+	&CheckerInfo{Name: "NotPanics", Params: []string{"function"}},
+}
+
+func (checker *notPanicsChecker) Check(params []interface{}, names []string) (result bool, error string) {
+	f := reflect.ValueOf(params[0])
+	if f.Kind() != reflect.Func || f.Type().NumIn() != 0 {
+		return false, "Function must take zero arguments"
+	}
+	defer func() {
+		// If the function has not panicked, then don't do the check.
+		if error != "" {
+			return
+		}
+		params[0] = recover()
+		names[0] = "panic"
+		result = params[0] == nil
+	}()
+	f.Call(nil)
+	return true, ""
+}
 
 type panicsChecker struct {
 	*CheckerInfo