Add PanicAssertionFunc (#1337, #730)

Add a `PanicAssertionFunc` to ease writing table-driven tests for panic
assertion.

Closes #730

Author: fahimbagar

assert/assertions.go

@@ -45,6 +45,10 @@ type BoolAssertionFunc func(TestingT, bool, ...interface{}) bool
 // for table driven tests.
 type ErrorAssertionFunc func(TestingT, error, ...interface{}) bool
 
+// PanicAssertionFunc is a common function prototype when validating a panic value.  Can be useful
+// for table driven tests.
+type PanicAssertionFunc = func(t TestingT, f PanicTestFunc, msgAndArgs ...interface{}) bool
+
 // Comparison is a custom function that returns true on success and false on failure
 type Comparison func() (success bool)
 

assert/assertions_test.go

@@ -2789,6 +2789,42 @@ func TestErrorAssertionFunc(t *testing.T) {
 	}
 }
 
+func ExamplePanicAssertionFunc() {
+	t := &testing.T{} // provided by test
+
+	tests := []struct {
+		name      string
+		panicFn   PanicTestFunc
+		assertion PanicAssertionFunc
+	}{
+		{"with panic", func() { panic(nil) }, Panics},
+		{"without panic", func() {}, NotPanics},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			tt.assertion(t, tt.panicFn)
+		})
+	}
+}
+
+func TestPanicAssertionFunc(t *testing.T) {
+	tests := []struct {
+		name      string
+		panicFn   PanicTestFunc
+		assertion PanicAssertionFunc
+	}{
+		{"not panic", func() {}, NotPanics},
+		{"panic", func() { panic(nil) }, Panics},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			tt.assertion(t, tt.panicFn)
+		})
+	}
+}
+
 func TestEventuallyFalse(t *testing.T) {
 	mockT := new(testing.T)