Added a 'expectedOutputNever' method for console command testing.

src/Illuminate/Foundation/Testing/Concerns/InteractsWithConsole.php

@@ -22,6 +22,13 @@ trait InteractsWithConsole
      */
     public $expectedOutput = [];
 
+    /**
+     * All of the output lines that are expected to never be output.
+     *
+     * @var array
+     */
+    public $expectedOutputNever = [];
+
     /**
      * All of the expected ouput tables.
      *

src/Illuminate/Testing/PendingCommand.php

@@ -133,6 +133,19 @@ public function expectsOutput($output)
         return $this;
     }
 
+    /**
+     * Specify output that should never be printed when the command runs.
+     *
+     * @param  string  $output
+     * @return $this
+     */
+    public function expectsOutputNever($output)
+    {
+        $this->test->expectedOutputNever[$output] = false;
+
+        return $this;
+    }
+
     /**
      * Specify a table that should be printed when the command runs.
      *
@@ -238,6 +251,10 @@ protected function verifyExpectations()
         if (count($this->test->expectedOutput)) {
             $this->test->fail('Output "'.Arr::first($this->test->expectedOutput).'" was not printed.');
         }
+
+        if ($output = array_search(true, $this->test->expectedOutputNever)) {
+            $this->test->fail('Output "'.$output.'" was printed.');
+        }
     }
 
     /**
@@ -299,6 +316,16 @@ private function createABufferedOutputMock()
                 });
         }
 
+        foreach ($this->test->expectedOutputNever as $output => $displayed) {
+            $mock->shouldReceive('doWrite')
+                ->once()
+                ->ordered()
+                ->with($output, Mockery::any())
+                ->andReturnUsing(function () use ($output) {
+                    $this->test->expectedOutputNever[$output] = true;
+                });
+        }
+
         return $mock;
     }