Less and Greater for numbers + example tests

Author: lainio

assert/assert.go

@@ -865,6 +865,32 @@ func Error(err error, a ...any) {
 	}
 }
 
+// Greater asserts that the value is greater than want. 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.
+//
+// Note that when [Plain] asserter is used ([SetDefault]), optional arguments
+// are used to override the auto-generated assert violation message.
+func Greater[T Number](val, want T, a ...any) {
+	if val <= want {
+		defMsg := fmt.Sprintf(assertionMsg+": got '%v', want <= '%v'", val, want)
+		current().reportAssertionFault(defMsg, a)
+	}
+}
+
+// Less asserts that the value is less than want. 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.
+//
+// Note that when [Plain] asserter is used ([SetDefault]), optional arguments
+// are used to override the auto-generated assert violation message.
+func Less[T Number](val, want T, a ...any) {
+	if val >= want {
+		defMsg := fmt.Sprintf(assertionMsg+": got '%v', want >= '%v'", val, want)
+		current().reportAssertionFault(defMsg, a)
+	}
+}
+
 // Zero asserts that the value is 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/assert_test.go

@@ -191,6 +191,36 @@ func ExampleSShorter() {
 	// Output: sample: assert_test.go:186: ExampleSShorter.func1(): assertion violation: got '1', should be shorter than '0': optional message (test_str)
 }
 
+func ExampleLess() {
+	sample := func(b int8) (err error) {
+		defer err2.Handle(&err, "sample")
+
+		assert.Equal(b, 1) // ok
+		assert.Less(b, 2)  // ok
+		assert.Less(b, 1)  // not ok
+		return err
+	}
+	var b int8 = 1
+	err := sample(b)
+	fmt.Printf("%v", err)
+	// Output: sample: assert_test.go:200: ExampleLess.func1(): assertion violation: got '1', want >= '1'
+}
+
+func ExampleGreater() {
+	sample := func(b int8) (err error) {
+		defer err2.Handle(&err, "sample")
+
+		assert.Equal(b, 2)   // ok
+		assert.Greater(b, 1) // ok
+		assert.Greater(b, 2) // not ok
+		return err
+	}
+	var b int8 = 2
+	err := sample(b)
+	fmt.Printf("%v", err)
+	// Output: sample: assert_test.go:215: ExampleGreater.func1(): assertion violation: got '2', want <= '2'
+}
+
 func assertZero(i int) {
 	assert.Zero(i)
 }