diff --git a/tests/C1/DumpExampleTest.php b/tests/C1/DumpExampleTest.php
new file mode 100644
index 0000000..3dcc87b
--- /dev/null
+++ b/tests/C1/DumpExampleTest.php
@@ -0,0 +1,29 @@
+<?php
+
+namespace Tests\C1;
+
+use App\DumpExample;
+use PHPUnit\Framework\TestCase;
+
+class DumpExampleTest extends TestCase
+{
+    public function test_return_1_when_input_true()
+    {
+        $sut = new DumpExample;
+
+        $actualResult = $sut->examine(true);
+
+        $expectedResult = 1;
+        $this->assertEquals($expectedResult, $actualResult);
+    }
+
+    public function test_return_0_when_input_false()
+    {
+        $sut = new DumpExample;
+
+        // Cause by division 0
+        $this->expectError();
+
+        $sut->examine(false);
+    }
+}
diff --git a/tests/C1/ProcessRunnerTest.php b/tests/C1/ProcessRunnerTest.php
new file mode 100644
index 0000000..406de78
--- /dev/null
+++ b/tests/C1/ProcessRunnerTest.php
@@ -0,0 +1,65 @@
+<?php
+
+namespace Tests\C1;
+
+use App\ProcessRunner;
+use PHPUnit\Framework\TestCase;
+
+class ProcessRunnerTest extends TestCase
+{
+    public function test_return_2_WHEN_pass_case_1_case_3()
+    {
+        $sut = new ProcessRunner;
+
+        $actualResult = $sut->run(12, 1);
+
+        $expectedResult = 2;
+        $this->assertEquals($expectedResult, $actualResult);
+        $this->assertTrue($sut->wasProcess1Called());
+        $this->assertFalse($sut->wasProcess2Called());
+        $this->assertTrue($sut->wasProcess3Called());
+        $this->assertFalse($sut->wasProcess4Called());
+    }
+
+    public function test_return_2_when_pass_case_1_case_4()
+    {
+        $sut = new ProcessRunner;
+
+        $actualResult = $sut->run(13, 1);
+
+        $expectedResult = 2;
+        $this->assertEquals($expectedResult, $actualResult);
+        $this->assertTrue($sut->wasProcess1Called());
+        $this->assertFalse($sut->wasProcess2Called());
+        $this->assertFalse($sut->wasProcess3Called());
+        $this->assertTrue($sut->wasProcess4Called());
+    }
+
+    public function test_return_2_when_pass_case_2_case_3()
+    {
+        $sut = new ProcessRunner;
+
+        $actualResult = $sut->run(7, 6);
+
+        $expectedResult = 2;
+        $this->assertEquals($expectedResult, $actualResult);
+        $this->assertFalse($sut->wasProcess1Called());
+        $this->assertTrue($sut->wasProcess2Called());
+        $this->assertTrue($sut->wasProcess3Called());
+        $this->assertFalse($sut->wasProcess4Called());
+    }
+
+    public function test_return_2_WHEN_pass_case_2_case_4()
+    {
+        $sut = new ProcessRunner;
+
+        $actualResult = $sut->run(1, 1);
+
+        $expectedResult = 2;
+        $this->assertEquals($expectedResult, $actualResult);
+        $this->assertFalse($sut->wasProcess1Called());
+        $this->assertTrue($sut->wasProcess2Called());
+        $this->assertFalse($sut->wasProcess3Called());
+        $this->assertTrue($sut->wasProcess4Called());
+    }
+}
diff --git a/tests/C1/UsernameValidationTest.php b/tests/C1/UsernameValidationTest.php
new file mode 100644
index 0000000..d445d22
--- /dev/null
+++ b/tests/C1/UsernameValidationTest.php
@@ -0,0 +1,68 @@
+<?php
+
+namespace Tests\C1;
+
+use App\UsernameValidation;
+use PHPUnit\Framework\TestCase;
+
+class UsernameValidationTest extends TestCase
+{
+    public function test_return_false_when_user_name_lt_min_length()
+    {
+        $sut = new UsernameValidation;
+
+        $actualResult = $sut->isValid('');
+
+        $this->assertFalse($actualResult);
+        $this->assertEquals('Minimum length is 1', $sut->getMessage());
+    }
+
+    public function test_return_false_when_user_name_gt_max_length()
+    {
+        $sut = new UsernameValidation;
+
+        $actualResult = $sut->isValid('012345678901234567890');
+
+        $this->assertFalse($actualResult);
+        $this->assertEquals('Maximum length is 20', $sut->getMessage());
+    }
+
+    public function test_return_false_when_user_name_not_allow_dash_begin_or_end()
+    {
+        $sut = new UsernameValidation;
+
+         $actualResult = $sut->isValid('-1234');
+
+         $this->assertFalse($actualResult);
+        $this->assertEquals('- cannot appear at begin or end of name', $sut->getMessage());
+    }
+
+    public function test_return_false_when_user_name_not_allow_double_dash()
+    {
+        $sut = new UsernameValidation;
+
+        $actualResult = $sut->isValid('1--2');
+
+        $this->assertFalse($actualResult);
+        $this->assertEquals('Only single - is allowed', $sut->getMessage());
+    }
+
+    public function test_return_false_when_user_name_not_allow_invalid_character()
+    {
+        $sut = new UsernameValidation;
+
+        $actualResult = $sut->isValid('@');
+
+        $this->assertFalse($actualResult);
+        $this->assertEquals('Invalid character. Use only letters, digits and -', $sut->getMessage());
+    }
+
+    public function test_return_true_when_user_name_valid()
+    {
+        $sut = new UsernameValidation;
+
+        $actualResult = $sut->isValid('lethibaongan');
+
+        $this->assertTrue($actualResult);
+    }
+}