Allow the initial test suite to be skipped

src/Command/InfectionCommand.php

@@ -174,6 +174,12 @@ protected function configure(): void
                 InputOption::VALUE_REQUIRED,
                 'Extra php options for the initial test runner. Will be ignored if --coverage option presented.'
             )
+            ->addOption(
+                'skip-initial-tests',
+                null,
+                InputOption::VALUE_NONE,
+                'Skips the initial test runs - requires the coverage to be provided via the --coverage option.'
+            )
             ->addOption(
                 'ignore-msi-with-no-mutations',
                 null,
@@ -240,6 +246,10 @@ private function startUp(): void
 
         $coverageChecker = $this->container->getCoverageRequirementChecker();
 
+        if ($coverageChecker->hasSkipInitialTestsWithoutCoverageOption()) {
+            throw CoverageDoesNotExistException::mustAlreadyExist();
+        }
+
         if (!$coverageChecker->hasDebuggerOrCoverageOption()) {
             throw CoverageDoesNotExistException::unableToGenerate();
         }
@@ -296,6 +306,7 @@ private function initContainer(InputInterface $input): void
             $input->getOption('no-progress'),
             $coverage === '' ? null : $coverage,
             $initialTestsPhpOptions === '' ? null : $initialTestsPhpOptions,
+            (bool) $input->getOption('skip-initial-tests'),
             $input->getOption('ignore-msi-with-no-mutations'),
             $minMsi === null ? null : (float) $minMsi,
             $minCoveredMsi === null ? null : (float) $minCoveredMsi,

src/Configuration/Configuration.php

@@ -73,6 +73,7 @@ class Configuration
     private $testFrameworkExtraOptions;
     private $coveragePath;
     private $skipCoverage;
+    private $skipInitialTests;
     private $debug;
     private $onlyCovered;
     private $formatter;
@@ -102,6 +103,7 @@ public function __construct(
         string $testFrameworkExtraOptions,
         string $coveragePath,
         bool $skipCoverage,
+        bool $skipInitialTests,
         bool $debug,
         bool $onlyCovered,
         string $formatter,
@@ -134,6 +136,7 @@ public function __construct(
         $this->testFrameworkExtraOptions = $testFrameworkExtraOptions;
         $this->coveragePath = $coveragePath;
         $this->skipCoverage = $skipCoverage;
+        $this->skipInitialTests = $skipInitialTests;
         $this->debug = $debug;
         $this->onlyCovered = $onlyCovered;
         $this->formatter = $formatter;
@@ -223,6 +226,11 @@ public function shouldSkipCoverage(): bool
         return $this->skipCoverage;
     }
 
+    public function shouldSkipInitialTests(): bool
+    {
+        return $this->skipInitialTests;
+    }
+
     public function isDebugEnabled(): bool
     {
         return $this->debug;

src/Configuration/ConfigurationFactory.php

@@ -93,6 +93,7 @@ public function create(
         SchemaConfiguration $schema,
         ?string $existingCoveragePath,
         ?string $initialTestsPhpOptions,
+        bool $skipInitialTests,
         string $logVerbosity,
         bool $debug,
         bool $onlyCovered,
@@ -140,6 +141,7 @@ public function create(
             self::retrieveTestFrameworkExtraOptions($testFrameworkExtraOptions, $schema),
             self::retrieveCoveragePath($coverageBasePath, $testFramework),
             $skipCoverage,
+            $skipInitialTests,
             $debug,
             $onlyCovered,
             $formatter,

src/Console/ConsoleOutput.php

@@ -129,4 +129,13 @@ public function logNotInControlOfExitCodes(): void
             'It is your responsibility to disable xdebug/phpdbg unless needed.',
         ]);
     }
+
+    public function logSkippingInitialTests(): void
+    {
+        $this->io->warning([
+            'Skipping the initial test run can be very dangerous.',
+            'It is your responsibility to ensure the tests are in a passing state to begin.',
+            'If this is not done then mutations may report as caught when they are not.',
+        ]);
+    }
 }

src/Container.php

@@ -290,7 +290,8 @@ public static function create(): self
                 $config = $container->getConfiguration();
 
                 return new CoverageRequirementChecker(
-                    $config->getCoveragePath() !== '',
+                    $config->shouldSkipCoverage(),
+                    $config->shouldSkipInitialTests(),
                     $config->getInitialTestsPhpOptions() ?? ''
                 );
             },
@@ -421,6 +422,7 @@ public function withDynamicParameters(
         bool $noProgress,
         ?string $existingCoveragePath,
         ?string $initialTestsPhpOptions,
+        bool $skipInitialTests,
         bool $ignoreMsiWithNoMutations,
         ?float $minMsi,
         ?float $minCoveredMsi,
@@ -450,6 +452,7 @@ static function (self $container) use ($configFile): SchemaConfiguration {
             static function (self $container) use (
                 $existingCoveragePath,
                 $initialTestsPhpOptions,
+                $skipInitialTests,
                 $logVerbosity,
                 $debug,
                 $onlyCovered,
@@ -468,6 +471,7 @@ static function (self $container) use (
                     $container->getSchemaConfiguration(),
                     $existingCoveragePath,
                     $initialTestsPhpOptions,
+                    $skipInitialTests,
                     $logVerbosity,
                     $debug,
                     $onlyCovered,

src/Engine.php

@@ -112,6 +112,13 @@ public function execute(int $threads): bool
 
     private function runInitialTestSuite(): void
     {
+        if ($this->config->shouldSkipInitialTests()) {
+            $this->consoleOutput->logSkippingInitialTests();
+            $this->assertCodeCoverageExists($this->config->getTestFramework());
+
+            return;
+        }
+
         $initialTestSuitProcess = $this->initialTestsRunner->run(
             $this->config->getTestFrameworkExtraOptions(),
             $this->config->shouldSkipCoverage(),
@@ -122,7 +129,7 @@ private function runInitialTestSuite(): void
             throw InitialTestsFailed::fromProcessAndAdapter($initialTestSuitProcess, $this->adapter);
         }
 
-        $this->assertCodeCoverageExists($initialTestSuitProcess, $this->config->getTestFramework());
+        $this->assertCodeCoverageProduced($initialTestSuitProcess, $this->config->getTestFramework());
 
         $this->memoryLimitApplier->applyMemoryLimitFromProcess($initialTestSuitProcess, $this->adapter);
     }
@@ -170,7 +177,22 @@ private function checkMetrics(): bool
         return true;
     }
 
-    private function assertCodeCoverageExists(Process $initialTestsProcess, string $testFrameworkKey): void
+    private function assertCodeCoverageExists(string $testFrameworkKey): void
+    {
+        $coverageDir = $this->config->getCoveragePath();
+
+        $coverageIndexFilePath = $coverageDir . '/' . PhpUnitXmlCoverageFactory::COVERAGE_INDEX_FILE_NAME;
+
+        if (!file_exists($coverageIndexFilePath)) {
+            throw CoverageDoesNotExistException::with(
+                $coverageIndexFilePath,
+                $testFrameworkKey,
+                dirname($coverageIndexFilePath, 2)
+            );
+        }
+    }
+
+    private function assertCodeCoverageProduced(Process $initialTestsProcess, string $testFrameworkKey): void
     {
         $coverageDir = $this->config->getCoveragePath();
 

src/Process/Coverage/CoverageRequirementChecker.php

@@ -46,11 +46,13 @@
 final class CoverageRequirementChecker
 {
     private $skipCoverage;
+    private $skipInitialTests;
     private $initialTestPhpOptions;
 
-    public function __construct(bool $skipCoverage, string $initialTestPhpOptions)
+    public function __construct(bool $skipCoverage, bool $skipInitialTests, string $initialTestPhpOptions)
     {
         $this->skipCoverage = $skipCoverage;
+        $this->skipInitialTests = $skipInitialTests;
         $this->initialTestPhpOptions = $initialTestPhpOptions;
     }
 
@@ -65,6 +67,11 @@ public function hasDebuggerOrCoverageOption(): bool
             || $this->isPcovIncludedInInitialTestPhpOptions();
     }
 
+    public function hasSkipInitialTestsWithoutCoverageOption(): bool
+    {
+        return $this->skipInitialTests && !$this->skipCoverage;
+    }
+
     private function isXdebugIncludedInInitialTestPhpOptions(): bool
     {
         return (bool) preg_match(

src/TestFramework/Coverage/CoverageDoesNotExistException.php

@@ -92,4 +92,9 @@ public static function unableToGenerate(): self
             self::INFECTION_USAGE_SUGGESTION
         );
     }
+
+    public static function mustAlreadyExist(): self
+    {
+        return new self('When skipping the initial test suite run, existing code coverage must be provided using --coverage');
+    }
 }

tests/e2e/Skip_Initial_Tests/README.md

@@ -0,0 +1,3 @@
+# Provide existing coverage files
+
+* Ensure the initial test suite is not run

tests/e2e/Skip_Initial_Tests/composer.json

@@ -0,0 +1,23 @@
+{
+    "config": {
+        "platform": {
+            "php": "7.2.9"
+        }
+    },
+    "require-dev": {
+        "phpunit/phpunit": "^6.5",
+        "phpspec/phpspec": "^4.3",
+        "leanphp/phpspec-code-coverage": "^4.0"
+    },
+    "autoload": {
+        "psr-4": {
+            "spec\\": "spec/",
+            "ProvideExistingCoverage\\": "src/"
+        }
+    },
+    "autoload-dev": {
+        "psr-4": {
+            "ProvideExistingCoverage\\Test\\": "tests/"
+        }
+    }
+}

tests/e2e/Skip_Initial_Tests/expected-output_phpspec.txt

@@ -0,0 +1,44 @@
+Total: 8
+Killed mutants:
+===============
+
+
+Errors mutants:
+===============
+
+
+Escaped mutants:
+================
+
+
+Timed Out mutants:
+==================
+
+
+Not Covered mutants:
+====================
+
+
+Mutator: PublicVisibility
+Line 7
+
+Mutator: Plus
+Line 9
+
+Mutator: TrueValue
+Line 12
+
+Mutator: PublicVisibility
+Line 12
+
+Mutator: FalseValue
+Line 14
+
+Mutator: NotIdentical
+Line 14
+
+Mutator: TrueValue
+Line 15
+
+Mutator: FalseValue
+Line 18

tests/e2e/Skip_Initial_Tests/expected-output_phpunit.txt

@@ -0,0 +1,44 @@
+Total: 8
+Killed mutants:
+===============
+
+
+Mutator: PublicVisibility
+Line 7
+
+Mutator: Plus
+Line 9
+
+Mutator: TrueValue
+Line 12
+
+Mutator: PublicVisibility
+Line 12
+
+Mutator: FalseValue
+Line 14
+
+Mutator: NotIdentical
+Line 14
+
+Mutator: TrueValue
+Line 15
+
+Errors mutants:
+===============
+
+
+Escaped mutants:
+================
+
+
+Timed Out mutants:
+==================
+
+
+Not Covered mutants:
+====================
+
+
+Mutator: FalseValue
+Line 18