Add more assertions to the test suite

tests/Unit/Configuration/ValidatorTest.php

@@ -83,6 +83,11 @@ public function provide_validators_with_given_value(): iterable
     public function it_accepts_null(Validator $validator, string $method): void
     {
         $config = new EditableConfig();
+        // set non-null values to test they will be changed
+        $config->setCachePath('/cache/path');
+        $config->setMaxScoreThreshold(1.0);
+        $config->setMinScoreToShow(1);
+
         $validator->validate($config, [$validator->getKey() => null]);
 
         $this->assertNull($config->$method());
@@ -99,33 +104,34 @@ public function provide_validators_accepting_null(): iterable
      * @test
      * @dataProvider provide_validators_with_invalid_value
      */
-    public function it_throws_with_invalid_value(Validator $validator, $invalidValue): void
+    public function it_throws_with_invalid_value(Validator $validator, $invalidValue, string $errorMessage): void
     {
         $config = new EditableConfig();
         $this->expectException(InvalidArgumentException::class);
+        $this->expectExceptionMessage($errorMessage);
         $validator->validate($config, [$validator->getKey() => $invalidValue]);
     }
 
     public function provide_validators_with_invalid_value(): iterable
     {
-        yield 'CachePath / int' => [new CachePath(), 123];
-        yield 'CommitsSince / int' => [new CommitsSince(), 123];
-        yield 'CommitsSince / null' => [new CommitsSince(), null];
-        yield 'DirectoriesToScan / string' => [new DirectoriesToScan(), 'foo'];
-        yield 'DirectoriesToScan / null' => [new DirectoriesToScan(), null];
-        yield 'FileExtensions / string' => [new FileExtensions(), 'foo'];
-        yield 'FileExtensions / null' => [new FileExtensions(), null];
-        yield 'FilesToIgnore / string' => [new FilesToIgnore(), 'foo'];
-        yield 'FilesToIgnore / null' => [new FilesToIgnore(), null];
-        yield 'FilesToShow / string' => [new FilesToShow(), 'foo'];
-        yield 'FilesToShow / null' => [new FilesToShow(), null];
-        yield 'Hooks / string' => [new Hooks(), 'foo'];
-        yield 'Hooks / null' => [new Hooks(), null];
-        yield 'MaxScoreThreshold / string' => [new MaxScoreThreshold(), 'foo'];
-        yield 'MinScoreToShow / string' => [new MinScoreToShow(), 'foo'];
-        yield 'ParallelJobs / string' => [new ParallelJobs(), 'foo'];
-        yield 'ParallelJobs / null' => [new ParallelJobs(), null];
-        yield 'Vcs / int' => [new Vcs(), 123];
-        yield 'Vcs / null' => [new Vcs(), null];
+        yield 'CachePath / int' => [new CachePath(), 123, 'Cache path should be a string'];
+        yield 'CommitsSince / int' => [new CommitsSince(), 123, 'Commits since should be a string'];
+        yield 'CommitsSince / null' => [new CommitsSince(), null, 'Commits since should be a string'];
+        yield 'DirectoriesToScan / string' => [new DirectoriesToScan(), 'foo', 'Directories to scan should be an array of strings'];
+        yield 'DirectoriesToScan / null' => [new DirectoriesToScan(), null, 'Directories to scan should be an array of strings'];
+        yield 'FileExtensions / string' => [new FileExtensions(), 'foo', 'File extensions should be an array of strings'];
+        yield 'FileExtensions / null' => [new FileExtensions(), null, 'File extensions should be an array of strings'];
+        yield 'FilesToIgnore / string' => [new FilesToIgnore(), 'foo', 'Files to ignore should be an array of strings'];
+        yield 'FilesToIgnore / null' => [new FilesToIgnore(), null, 'Files to ignore should be an array of strings'];
+        yield 'FilesToShow / string' => [new FilesToShow(), 'foo', 'Files to show should be an integer'];
+        yield 'FilesToShow / null' => [new FilesToShow(), null, 'Files to show should be an integer'];
+        yield 'Hooks / string' => [new Hooks(), 'foo', 'Hooks should be an array of strings'];
+        yield 'Hooks / null' => [new Hooks(), null, 'Hooks should be an array of strings'];
+        yield 'MaxScoreThreshold / string' => [new MaxScoreThreshold(), 'foo', 'Maximum score threshold should be a number'];
+        yield 'MinScoreToShow / string' => [new MinScoreToShow(), 'foo', 'Minimum score to show should be a number'];
+        yield 'ParallelJobs / string' => [new ParallelJobs(), 'foo', 'Amount of parallel jobs should be an integer'];
+        yield 'ParallelJobs / null' => [new ParallelJobs(), null, 'Amount of parallel jobs should be an integer'];
+        yield 'Vcs / int' => [new Vcs(), 123, 'VCS should be a string'];
+        yield 'Vcs / null' => [new Vcs(), null, 'VCS should be a string'];
     }
 }

tests/Unit/File/FileHelperTest.php

@@ -4,11 +4,20 @@
 
 namespace Churn\Tests\Unit\File;
 
+use InvalidArgumentException;
 use Churn\File\FileHelper;
 use Churn\Tests\BaseTestCase;
+use Symfony\Component\Filesystem\Filesystem;
 
 class FileHelperTest extends BaseTestCase
 {
+    /** @var string[] */
+    private $filesToDelete = [];
+
+    protected function tearDown()
+    {
+        (new Filesystem())->remove($this->filesToDelete);
+    }
 
     /**
      * @test
@@ -50,4 +59,41 @@ public function provide_relative_paths(): iterable
             yield ['C:\\foo\\file.php', 'C:\\foo\\', 'file.php'];
         }
     }
+
+    /**
+     * @test
+     * @dataProvider provide_writable_paths
+     */
+    public function it_can_ensure_a_file_is_writable(string $filePath): void
+    {
+        $dirPath = \dirname($filePath);
+
+        FileHelper::ensureFileIsWritable($filePath);
+
+        $this->assertTrue(\is_dir($dirPath), "Directory should exist: " . $dirPath);
+    }
+
+    public function provide_writable_paths(): iterable
+    {
+        yield [__FILE__];
+        yield [__DIR__ . '/non-existing-file'];
+        $this->filesToDelete[] = __DIR__ . '/path';
+        yield [__DIR__ . '/path/to/non-existing-file'];
+    }
+
+    /**
+     * @test
+     * @dataProvider provide_invalid_writable_paths
+     */
+    public function it_throws_with_invalid_writable_files(string $filePath): void
+    {
+        $this->expectException(InvalidArgumentException::class);
+        FileHelper::ensureFileIsWritable($filePath);
+    }
+
+    public function provide_invalid_writable_paths(): iterable
+    {
+        yield [''];
+        yield [__DIR__];
+    }
 }

tests/Unit/Process/CacheProcessFactoryTest.php

@@ -16,16 +16,18 @@ class CacheProcessFactoryTest extends BaseTestCase
      * @test
      * @dataProvider provide_invalid_paths
      */
-    public function it_throws_for_invalid_cache_path(string $cachePath): void
+    public function it_throws_for_invalid_cache_path(string $cachePath, string $errorMessage): void
     {
         $factory = m::mock(ProcessFactory::class);
         $this->expectException(InvalidArgumentException::class);
+        $this->expectExceptionMessage('Invalid cache file path: ' . $errorMessage);
+        $this->expectExceptionCode(0);
         new CacheProcessFactory($cachePath, $factory);
     }
 
     public function provide_invalid_paths(): iterable
     {
-        yield [''];
-        yield [__DIR__];
+        yield ['', 'Path cannot be empty'];
+        yield [__DIR__, 'Path cannot be a folder'];
     }
 }

tests/Unit/Process/ConcreteProcessFactoryTest.php

@@ -76,7 +76,8 @@ public function it_throws_exception_if_VCS_is_not_supported()
     {
         $config = new Config();
         $this->expectException(InvalidArgumentException::class);
-        $this->processFactory = new ConcreteProcessFactory('not a valid VCS', $config->getCommitsSince());
+        $this->expectExceptionMessage('Unsupported VCS: not a valid VCS');
+        new ConcreteProcessFactory('not a valid VCS', $config->getCommitsSince());
     }
 
     /** @test */

tests/Unit/Result/ResultsRendererFactoryTest.php

@@ -47,7 +47,8 @@ public function it_returns_the_console_renderer_when_provided_text_format()
     public function it_throws_exception_if_format_is_invalid()
     {
         $this->expectException(InvalidArgumentException::class);
-        $this->assertInstanceOf(ConsoleResultsRenderer::class, $this->factory->getRenderer('foobar'));
+        $this->expectExceptionMessage('Invalid output format provided');
+        $this->factory->getRenderer('foobar');
     }
 
     public function setUp()