Add libsvm exception tests (#202)

src/Phpml/Exception/LibsvmCommandException.php

@@ -8,8 +8,8 @@ use Exception;
 
 class LibsvmCommandException extends Exception
 {
-    public static function failedToRun(string $command): self
+    public static function failedToRun(string $command, string $reason): self
     {
-        return new self(sprintf('Failed running libsvm command: "%s"', $command));
+        return new self(sprintf('Failed running libsvm command: "%s" with reason: "%s"', $command, $reason));
     }
 }

src/Phpml/SupportVectorMachine/SupportVectorMachine.php

@@ -153,16 +153,17 @@ class SupportVectorMachine
         $modelFileName = $trainingSetFileName.'-model';
 
         $command = $this->buildTrainCommand($trainingSetFileName, $modelFileName);
-        $output = '';
-        exec(escapeshellcmd($command), $output, $return);
+        $output = [];
+        exec(escapeshellcmd($command).' 2>&1', $output, $return);
+
+        unlink($trainingSetFileName);
 
         if ($return !== 0) {
-            throw LibsvmCommandException::failedToRun($command);
+            throw LibsvmCommandException::failedToRun($command, array_pop($output));
         }
 
         $this->model = file_get_contents($modelFileName);
 
-        unlink($trainingSetFileName);
         unlink($modelFileName);
     }
 
@@ -184,19 +185,19 @@ class SupportVectorMachine
         $outputFileName = $testSetFileName.'-output';
 
         $command = sprintf('%ssvm-predict%s %s %s %s', $this->binPath, $this->getOSExtension(), $testSetFileName, $modelFileName, $outputFileName);
-        $output = '';
-        exec(escapeshellcmd($command), $output, $return);
-
-        if ($return !== 0) {
-            throw LibsvmCommandException::failedToRun($command);
-        }
-
-        $predictions = file_get_contents($outputFileName);
+        $output = [];
+        exec(escapeshellcmd($command).' 2>&1', $output, $return);
 
         unlink($testSetFileName);
         unlink($modelFileName);
+        $predictions = file_get_contents($outputFileName);
+
         unlink($outputFileName);
 
+        if ($return !== 0) {
+            throw LibsvmCommandException::failedToRun($command, array_pop($output));
+        }
+
         if (in_array($this->type, [Type::C_SVC, Type::NU_SVC])) {
             $predictions = DataTransformer::predictions($predictions, $this->targets);
         } else {

tests/Phpml/SupportVectorMachine/SupportVectorMachineTest.php

@@ -5,6 +5,7 @@ declare(strict_types=1);
 namespace Phpml\Tests\SupportVectorMachine;
 
 use Phpml\Exception\InvalidArgumentException;
+use Phpml\Exception\LibsvmCommandException;
 use Phpml\SupportVectorMachine\Kernel;
 use Phpml\SupportVectorMachine\SupportVectorMachine;
 use Phpml\SupportVectorMachine\Type;
@@ -105,4 +106,22 @@ SV
         $svm = new SupportVectorMachine(Type::C_SVC, Kernel::RBF);
         $svm->setBinPath('var');
     }
+
+    public function testThrowExceptionWhenLibsvmFailsDuringTrain(): void
+    {
+        $this->expectException(LibsvmCommandException::class);
+        $this->expectExceptionMessage('ERROR: unknown svm type');
+
+        $svm = new SupportVectorMachine(99, Kernel::RBF);
+        $svm->train([], []);
+    }
+
+    public function testThrowExceptionWhenLibsvmFailsDuringPredict(): void
+    {
+        $this->expectException(LibsvmCommandException::class);
+        $this->expectExceptionMessage('can\'t open model file');
+
+        $svm = new SupportVectorMachine(Type::C_SVC, Kernel::RBF);
+        $svm->predict([1]);
+    }
 }