add toBeBetween() expectation

tests/Features/Expect/toBeBetween.php

@@ -0,0 +1,43 @@
+<?php
+
+use PHPUnit\Framework\ExpectationFailedException;
+
+test('passes with int', function () {
+    expect(2)->toBeBetween(1, 3);
+});
+
+test('passes with float', function () {
+    expect(1.5)->toBeBetween(1.25, 1.75);
+});
+
+test('passes with float and int', function () {
+    expect(1.5)->toBeBetween(1, 2);
+});
+
+test('passes with DateTime', function () {
+    expect(new DateTime('2023-09-22'))->toBeBetween(new DateTime('2023-09-21'), new DateTime('2023-09-23'));
+});
+
+test('failure with int', function () {
+    expect(4)->toBeBetween(1, 3);
+})->throws(ExpectationFailedException::class);
+
+test('failure with float', function () {
+    expect(2)->toBeBetween(1.5, 1.75);
+})->throws(ExpectationFailedException::class);
+
+test('failure with float and int', function () {
+    expect(2.1)->toBeBetween(1, 2);
+})->throws(ExpectationFailedException::class);
+
+test('failure with DateTime', function () {
+    expect(new DateTime('2023-09-20'))->toBeBetween(new DateTime('2023-09-21'), new DateTime('2023-09-23'));
+})->throws(ExpectationFailedException::class);
+
+test('failures with custom message', function () {
+    expect(4)->toBeBetween(1, 3, 'oh no!');
+})->throws(ExpectationFailedException::class, 'oh no!');
+
+test('not failures', function () {
+    expect(2)->not->toBeBetween(1, 3);
+})->throws(ExpectationFailedException::class);