diff --git a/tests/src/Generator/DefaultTimeGeneratorTest.php b/tests/src/Generator/DefaultTimeGeneratorTest.php
index 377511f..2d9fe5c 100644
--- a/tests/src/Generator/DefaultTimeGeneratorTest.php
+++ b/tests/src/Generator/DefaultTimeGeneratorTest.php
@@ -2,36 +2,151 @@
 
 namespace Ramsey\Uuid\Test\Generator;
 
+use Ramsey\Uuid\Converter\TimeConverterInterface;
+use Ramsey\Uuid\Generator\DefaultTimeGenerator;
+use Ramsey\Uuid\Provider\NodeProviderInterface;
+use Ramsey\Uuid\Provider\TimeProviderInterface;
 use Ramsey\Uuid\Test\TestCase;
+use Mockery;
+use AspectMock\Test AS AspectMock;
 
 class DefaultTimeGeneratorTest extends TestCase
 {
-    public function testGenerateUsesTimeProvidersCurrentTime()
+    /** @var  TimeProviderInterface */
+    private $timeProvider;
+    /** @var  NodeProviderInterface */
+    private $nodeProvider;
+    /** @var  TimeConverterInterface */
+    private $timeConverter;
+    /** @var string */
+    private $nodeId = '122f80ca9e06';
+    /** @var int[] */
+    private $currentTime;
+    /** @var string[] */
+    private $calculatedTime;
+    /** @var int */
+    private $clockSeq = 4066;
+
+
+    public function setUp()
     {
+        parent::setUp();
+        $this->timeProvider = $this->getMock('Ramsey\Uuid\Provider\TimeProviderInterface');
+        $this->nodeProvider = $this->getMock('Ramsey\Uuid\Provider\NodeProviderInterface');
+        $this->timeConverter = $this->getMock('Ramsey\Uuid\Converter\TimeConverterInterface');
+        $this->currentTime = ["sec" => 1458733431, "usec" => 877449];
+        $this->calculatedTime = ["low" => "83cb98e0", "mid" => "98e0", "hi" => "03cb"];
     }
 
-    public function testGenerateCalculatesTimeWithConverter()
-    {
-    }
-
-    public function testGenerateAppliesVersionToTime()
-    {
-    }
-
-    public function testGenerateAppliesVariantToClockSequence()
-    {
-    }
-
-    public function testGenerateReturnsBinaryStringInUuidFormat()
+    public function tearDown()
     {
+        parent::tearDown();
+        $this->timeProvider = null;
+        $this->nodeProvider = null;
+        $this->timeConverter = null;
+        Mockery::close();
+        AspectMock::clean();
     }
 
     public function testGenerateUsesNodeProviderWhenNodeIsNull()
     {
+        $this->nodeProvider->expects($this->once())
+            ->method('getNode')
+            ->willReturn('122f80ca9e06');
+        $defaultTimeGenerator = new DefaultTimeGenerator($this->nodeProvider, $this->timeConverter, $this->timeProvider);
+        $defaultTimeGenerator->generate();
     }
 
+    public function testGenerateUsesTimeProvidersCurrentTime()
+    {
+        $this->timeProvider->expects($this->once())
+            ->method('currentTime')
+            ->willReturn($this->currentTime);
+        $defaultTimeGenerator = new DefaultTimeGenerator($this->nodeProvider, $this->timeConverter, $this->timeProvider);
+        $defaultTimeGenerator->generate($this->nodeId);
+    }
+
+    public function testGenerateCalculatesTimeWithConverter()
+    {
+        $this->timeProvider->method('currentTime')
+            ->willReturn($this->currentTime);
+        $this->timeConverter->expects($this->once())
+            ->method('calculateTime')
+            ->with($this->currentTime['sec'], $this->currentTime['usec'])
+            ->willReturn($this->calculatedTime);
+        $defaultTimeGenerator = new DefaultTimeGenerator($this->nodeProvider, $this->timeConverter, $this->timeProvider);
+        $defaultTimeGenerator->generate($this->nodeId);
+    }
+
+    /**
+     * @runInSeparateProcess
+     * @preserveGlobalState disabled
+     */
+    public function testGenerateAppliesVersionAndVariant()
+    {
+        $this->timeProvider->method('currentTime')
+            ->willReturn($this->currentTime);
+        $this->timeConverter->method('calculateTime')
+            ->with($this->currentTime['sec'], $this->currentTime['usec'])
+            ->willReturn($this->calculatedTime);
+        $binaryUtils = Mockery::mock('alias:Ramsey\Uuid\BinaryUtils');
+        $binaryUtils->shouldReceive('applyVersion')
+            ->with($this->calculatedTime['hi'], 1)
+            ->andReturn(971);
+        $clockSeqShifted = 15;
+        $binaryUtils->shouldReceive('applyVariant')
+            ->with($clockSeqShifted)
+            ->andReturn(143);
+
+        $defaultTimeGenerator = new DefaultTimeGenerator($this->nodeProvider, $this->timeConverter, $this->timeProvider);
+        $defaultTimeGenerator->generate($this->nodeId, $this->clockSeq);
+    }
+
+    /**
+     * @runInSeparateProcess
+     * @preserveGlobalState disabled
+     */
+    public function testGenerateReturnsBinaryStringInUuidFormat()
+    {
+        $this->timeProvider->method('currentTime')->willReturn($this->currentTime);
+        $this->timeConverter->method('calculateTime')->willReturn($this->calculatedTime);
+        $binaryUtils = Mockery::mock('alias:Ramsey\Uuid\BinaryUtils');
+        $binaryUtils->shouldReceive('applyVersion')->andReturn(971);
+        $binaryUtils->shouldReceive('applyVariant')->andReturn(143);
+
+        $defaultTimeGenerator = new DefaultTimeGenerator($this->nodeProvider, $this->timeConverter, $this->timeProvider);
+        $result = $defaultTimeGenerator->generate($this->nodeId, $this->clockSeq);
+        /**
+         * // Given we use values:
+         * $low = '83cb98e0';
+         * $mid = '98e0';
+         * $timeHi = 971;
+         * $clockSeqHi = 143;
+         * $clockSeq = 4066;
+         * $node = '122f80ca9e06';
+         *
+         * $values = [$low, $mid, sprintf('%04x', $timeHi), sprintf('%02x', $clockSeqHi), sprintf('%02x', $clockSeq & 0xff), $node];
+         *
+         * // then:
+         * $hex = vsprintf('%08s%04s%04s%02s%02s%012s', $values);
+         */
+        $hex = '83cb98e098e003cb8fe2122f80ca9e06';
+        $binary = hex2bin($hex);
+        $this->assertEquals($binary, $result);
+    }
+
+    /**
+     * @runInSeparateProcess
+     * @preserveGlobalState disabled
+     */
     public function testGenerateUsesRandomSequenceWhenClockSeqNull()
     {
+        $this->skipIfHhvm();
+        $mt_rand = AspectMock::func('Ramsey\Uuid\Generator', 'mt_rand', 9622);
+        $defaultTimeGenerator = new DefaultTimeGenerator($this->nodeProvider, $this->timeConverter, $this->timeProvider);
+        $defaultTimeGenerator->generate($this->nodeId);
+        $mt_rand->verifyInvokedOnce([0, 16384]);
     }
 
+
 }