[11.x] assertSee handle empty values (#47597)

* fail when `assertSee` is passed an empty value

currently when passing an empty value to `assertSee` the test will pass.  these values include:

- `null`
- `[]`
- `''`
- `['foo', '', 'bar']`

rarely (IMO) is this the desired behavior, and may create false confidence in the test.

this change will fail the test by default when passed empty values, but also allow users to override if appropriate.

* minor formatting

* minor formatting

* Update TestResponse.php

---------

Co-authored-by: Taylor Otwell <[email protected]>

Author: browner12

src/Illuminate/Testing/TestResponse.php

@@ -518,13 +518,21 @@ public function assertStreamedContent($value)
      * @param  bool  $escape
      * @return $this
      */
-    public function assertSee($value, $escape = true)
+    public function assertSee($value, $escape = true, $allowEmptyValues = false)
     {
         $value = Arr::wrap($value);
 
+        if (! $allowEmptyValues && empty($value)) {
+            PHPUnit::fail('An empty value was passed to `assertSee`.');
+        }
+
         $values = $escape ? array_map('e', $value) : $value;
 
         foreach ($values as $value) {
+            if (! $allowEmptyValues && (string) $value === '') {
+                PHPUnit::fail('An empty value was passed to `assertSee`.');
+            }
+
             PHPUnit::assertStringContainsString((string) $value, $this->getContent());
         }
 

tests/Testing/TestResponseTest.php

@@ -329,6 +329,62 @@ public function testAssertSeeEscapedCanFail()
         $response->assertSee(['bar & baz', 'baz & qux']);
     }
 
+    public function testAssertSeeCatchesNullValue()
+    {
+        $this->expectException(AssertionFailedError::class);
+
+        $response = $this->makeMockResponse([
+            'render' => '<ul><li>foo</li><li>bar</li><li>baz</li><li>foo</li></ul>',
+        ]);
+
+        $response->assertSee(null);
+    }
+
+    public function testAssertSeeCatchesEmptyArray()
+    {
+        $this->expectException(AssertionFailedError::class);
+
+        $response = $this->makeMockResponse([
+            'render' => '<ul><li>foo</li><li>bar</li><li>baz</li><li>foo</li></ul>',
+        ]);
+
+        $response->assertSee([]);
+    }
+
+    public function testAssertSeeCatchesEmptyString()
+    {
+        $this->expectException(AssertionFailedError::class);
+
+        $response = $this->makeMockResponse([
+            'render' => '<ul><li>foo</li><li>bar</li><li>baz</li><li>foo</li></ul>',
+        ]);
+
+        $response->assertSee('');
+    }
+
+    public function testAssertSeeCatchesEmptyStringInArray()
+    {
+        $this->expectException(AssertionFailedError::class);
+
+        $response = $this->makeMockResponse([
+            'render' => '<ul><li>foo</li><li>bar</li><li>baz</li><li>foo</li></ul>',
+        ]);
+
+        $response->assertSee(['foo', '', 'bar']);
+    }
+
+    public function testAssertSeeAllowsEmptyValues()
+    {
+        $response = $this->makeMockResponse([
+            'render' => '<ul><li>foo</li><li>bar</li><li>baz</li><li>foo</li></ul>',
+        ]);
+
+        $response->assertSee(null, allowEmptyValues: true);
+        $response->assertSee([], allowEmptyValues: true);
+        $response->assertSee('', allowEmptyValues: true);
+        $response->assertSee(['foo', '', 'bar'], allowEmptyValues: true);
+    }
+
     public function testAssertSeeInOrder()
     {
         $response = $this->makeMockResponse([