diff --git a/test/EvallerTest.php b/test/EvallerTest.php
index 1e11317..1efc859 100644
--- a/test/EvallerTest.php
+++ b/test/EvallerTest.php
@@ -16,7 +16,9 @@ use MadLisp\Printer;
 use MadLisp\Reader;
 use MadLisp\Symbol;
 use MadLisp\Tokenizer;
+use MadLisp\UserFunc;
 use MadLisp\Vector;
+use MadLisp\Lib\Compare;
 use MadLisp\Lib\Math;
 
 class EvallerTest extends TestCase
@@ -188,13 +190,268 @@ class EvallerTest extends TestCase
         $evaller->eval($input, $env);
     }
 
+    public function testDebug()
+    {
+        $evaller = $this->getEvaller();
+
+        $this->assertFalse($evaller->getDebug());
+        $evaller->setDebug(true);
+        $this->assertTrue($evaller->getDebug());
+    }
+
+    // -------------------
+    // Tests special forms
+    // -------------------
+
+    public function andProvider(): array
+    {
+        return [
+            [[], true],
+            [[1, 2, 0, 3], 0],
+            [[1, 2, 3], 3]
+        ];
+    }
+
+    /**
+     * @dataProvider andProvider
+     */
+    public function testAnd(array $args, $expected)
+    {
+        $env = $this->getEnv();
+        $evaller = $this->getEvaller();
+
+        $input = new MList(array_merge([new Symbol('and')], $args));
+
+        $this->assertSame($expected, $evaller->eval($input, $env));
+    }
+
+    public function caseProvider(): array
+    {
+        return [
+            [
+                [
+                    new MList([new Symbol('+'), 1, 2]),
+                    new MList([2, "two"]),
+                    new MList([3, "three"]),
+                    new MList([4, "four"])
+                ],
+                "three"
+            ],
+            [
+                [
+                    new MList([new Symbol('+'), 2, 3]),
+                    new MList([2, "two"]),
+                    new MList([3, "three"]),
+                    new MList([4, "four"]),
+                    new MList([new Symbol('else'), 'other'])
+                ],
+                "other"
+            ]
+        ];
+    }
+
+    /**
+     * @dataProvider caseProvider
+     */
+    public function testCase(array $args, $expected)
+    {
+        $env = $this->getEnv();
+        $evaller = $this->getEvaller();
+
+        $input = new MList(array_merge([new Symbol('case')], $args));
+
+        $this->assertSame($expected, $evaller->eval($input, $env));
+    }
+
+    public function condProvider(): array
+    {
+        return [
+            [
+                [
+                    new MList([new MList([new Symbol('='), new Symbol('n'), 2]), "two"]),
+                    new MList([new MList([new Symbol('='), new Symbol('n'), 4]), "four"]),
+                    new MList([new MList([new Symbol('='), new Symbol('n'), 6]), "six"]),
+                ],
+                "four"
+            ],
+            [
+                [
+                    new MList([new MList([new Symbol('='), new Symbol('n'), 1]), "one"]),
+                    new MList([new MList([new Symbol('='), new Symbol('n'), 3]), "three"]),
+                    new MList([new MList([new Symbol('='), new Symbol('n'), 5]), "five"]),
+                    new MList([new Symbol('else'), 'other'])
+                ],
+                "other"
+            ]
+        ];
+    }
+
+    /**
+     * @dataProvider condProvider
+     */
+    public function testCond(array $args, $expected)
+    {
+        $env = $this->getEnv();
+        $evaller = $this->getEvaller();
+
+        $env->set('n', 4);
+
+        $input = new MList(array_merge([new Symbol('cond')], $args));
+
+        $this->assertSame($expected, $evaller->eval($input, $env));
+    }
+
+    public function testDef()
+    {
+        $env = $this->getEnv();
+        $evaller = $this->getEvaller();
+
+        $input = new MList([new Symbol('def'), new Symbol('abc'), 123]);
+
+        $evaller->eval($input, $env);
+
+        $this->assertSame($env->get('abc'), 123);
+    }
+
+    public function testEnv()
+    {
+        $env = $this->getEnv();
+        $evaller = $this->getEvaller();
+
+        $input = new MList([new Symbol('env')]);
+
+        $this->assertSame($env, $evaller->eval($input, $env));
+    }
+
+    public function testEval()
+    {
+        $env = $this->getEnv();
+        $evaller = $this->getEvaller();
+
+        $input = new MList([new Symbol('eval'), new MList([new Symbol('quote'), new MList([new Symbol('+'), 1, 2])])]);
+
+        $this->assertSame(3, $evaller->eval($input, $env));
+    }
+
+    public function testFn()
+    {
+        $env = $this->getEnv();
+        $evaller = $this->getEvaller();
+
+        $input = new MList([new Symbol('fn'), new MList([]), new MList([])]);
+
+        $result = $evaller->eval($input, $env);
+
+        $this->assertInstanceOf(UserFunc::class, $result);
+    }
+
+    public function ifProvider(): array
+    {
+        return [
+            [[new MList([new Symbol('<'), 1, 2]), "yes", "no"], "yes"],
+            [[new MList([new Symbol('>'), 1, 2]), "yes", "no"], "no"],
+
+            [[new MList([new Symbol('>'), 1, 2]), "yes"], null],
+        ];
+    }
+
+    /**
+     * @dataProvider ifProvider
+     */
+    public function testIf(array $args, $expected)
+    {
+        $env = $this->getEnv();
+        $evaller = $this->getEvaller();
+
+        $input = new MList(array_merge([new Symbol('if')], $args));
+
+        $this->assertSame($expected, $evaller->eval($input, $env));
+    }
+
+    public function testLet()
+    {
+        $env = $this->getEnv();
+        $evaller = $this->getEvaller();
+
+        $input = new MList([new Symbol('let'), new MList([
+                new Symbol('a'), new MList([new Symbol('+'), 1, 2]),
+                new Symbol('b'), new MList([new Symbol('*'), new Symbol('a'), 3])
+            ]),
+            new MList([new Symbol('*'), new Symbol('b'), 4])
+        ]);
+
+        $this->assertSame(36, $evaller->eval($input, $env));
+    }
+
+    public function orProvider(): array
+    {
+        return [
+            [[], false],
+            [[0, false, 2, 3], 2],
+            [[0, 1], 1]
+        ];
+    }
+
+    /**
+     * @dataProvider orProvider
+     */
+    public function testOr(array $args, $expected)
+    {
+        $env = $this->getEnv();
+        $evaller = $this->getEvaller();
+
+        $input = new MList(array_merge([new Symbol('or')], $args));
+
+        $this->assertSame($expected, $evaller->eval($input, $env));
+    }
+
+    public function testQuote()
+    {
+        $env = $this->getEnv();
+        $evaller = $this->getEvaller();
+
+        $input = new MList([new Symbol('quote'), new MList([new Symbol('+'), 1, 2])]);
+
+        $result = $evaller->eval($input, $env);
+
+        $this->assertInstanceOf(MList::class, $result);
+        $data = $result->getData();
+        $this->assertCount(3, $data);
+        $this->assertInstanceOf(Symbol::class, $data[0]);
+        $this->assertSame('+', $data[0]->getName());
+        $this->assertSame(1, $data[1]);
+        $this->assertSame(2, $data[2]);
+    }
+
+    public function testUndef()
+    {
+        $env = $this->getEnv();
+        $evaller = $this->getEvaller();
+
+        $env->set('aa', 12);
+
+        $this->assertTrue($env->has('aa'));
+
+        $input = new MList([new Symbol('undef'), new Symbol('aa')]);
+
+        $evaller->eval($input, $env);
+
+        $this->assertFalse($env->has('aa'));
+    }
+
+    // -----------------
+    // End special forms
+    // -----------------
+
     private function getEnv(): Env
     {
         $env = new Env('env');
 
-        // Define some math functions for testing
+        // Define some functions for testing
         $lib = new Math();
         $lib->register($env);
+        $lib = new Compare();
+        $lib->register($env);
 
         return $env;
     }
diff --git a/test/LispTest.php b/test/LispTest.php
new file mode 100644
index 0000000..53f11ae
--- /dev/null
+++ b/test/LispTest.php
@@ -0,0 +1,110 @@
+<?php
+/**
+ * MadLisp language
+ * @link http://madlisp.com/
+ * @copyright Copyright (c) 2020 Pekka Laiho
+ */
+
+use PHPUnit\Framework\TestCase;
+
+use MadLisp\Env;
+use MadLisp\Evaller;
+use MadLisp\Lisp;
+use MadLisp\Printer;
+use MadLisp\Reader;
+use MadLisp\Tokenizer;
+use MadLisp\Lib\Math;
+
+class LispTest extends TestCase
+{
+    public function testPrint()
+    {
+        $tokenizer = $this->createMock(Tokenizer::class);
+        $reader = $this->createMock(Reader::class);
+        $printer = $this->createMock(Printer::class);
+        $evaller = $this->createMock(Evaller::class);
+
+        $printer->expects($this->once())
+            ->method('print')
+            ->with($this->equalTo("abc"), $this->equalTo(false));
+
+        $lisp = new Lisp($tokenizer, $reader, $evaller, $printer, new Env('env'));
+
+        $lisp->print('abc', false);
+    }
+
+    public function testReadEval()
+    {
+        $tokenizer = $this->createMock(Tokenizer::class);
+        $reader = $this->createMock(Reader::class);
+        $printer = $this->createMock(Printer::class);
+        $evaller = $this->createMock(Evaller::class);
+
+        $tokenizer->expects($this->once())
+            ->method('tokenize');
+
+        $reader->expects($this->once())
+            ->method('read');
+
+        $evaller->expects($this->once())
+            ->method('eval');
+
+        $lisp = new Lisp($tokenizer, $reader, $evaller, $printer, new Env('env'));
+
+        $lisp->readEval('abc');
+    }
+
+    public function repProvider(): array
+    {
+        // This tests all main components together:
+        // Tokenizer, Reader, Evaller, Printer
+
+        return [
+            ['[(- (+ 2 3) 4) (- (* 2 3) 4)]', false, '[1 2]'],
+
+            ['"string"', false, 'string'],
+            ['"string"', true, '"string"'],
+        ];
+    }
+
+    /**
+     * @dataProvider repProvider
+     */
+    public function testRep(string $input, bool $readable, string $expected)
+    {
+        $tokenizer = new Tokenizer();
+        $reader = new Reader();
+        $printer = new Printer();
+        $evaller = new Evaller($tokenizer, $reader, $printer, false);
+
+        // Define some math functions for testing
+        $env = new Env('env');
+        $lib = new Math();
+        $lib->register($env);
+
+        $lisp = new Lisp($tokenizer, $reader, $evaller, $printer, $env);
+
+        ob_start();
+        $lisp->rep($input, $readable);
+        $result = ob_get_contents();
+        ob_end_clean();
+
+        $this->assertSame($expected, $result);
+    }
+
+    public function testSetDebug()
+    {
+        $tokenizer = $this->createMock(Tokenizer::class);
+        $reader = $this->createMock(Reader::class);
+        $printer = $this->createMock(Printer::class);
+        $evaller = $this->createMock(Evaller::class);
+
+        $evaller->expects($this->once())
+            ->method('setDebug')
+            ->with($this->equalTo(true));
+
+        $lisp = new Lisp($tokenizer, $reader, $evaller, $printer, new Env('env'));
+
+        $lisp->setDebug(true);
+    }
+}
diff --git a/test/PrinterTest.php b/test/PrinterTest.php
index 2fcd06e..13028e7 100644
--- a/test/PrinterTest.php
+++ b/test/PrinterTest.php
@@ -47,13 +47,28 @@ class PrinterTest extends TestCase
     /**
      * @dataProvider notReadableProvider
      */
-    public function testPrintNotReadable($input, string $expected)
+    public function testPrintStringNotReadable($input, string $expected)
     {
         $printer = new Printer();
         $result = $printer->pstr($input, false);
         $this->assertSame($expected, $result);
     }
 
+    /**
+     * @dataProvider notReadableProvider
+     */
+    public function testPrintNotReadable($input, string $expected)
+    {
+        $printer = new Printer();
+
+        ob_start();
+        $printer->print($input, false);
+        $result = ob_get_contents();
+        ob_end_clean();
+
+        $this->assertSame($expected, $result);
+    }
+
     public function readableProvider(): array
     {
         return [
@@ -69,13 +84,28 @@ class PrinterTest extends TestCase
     /**
      * @dataProvider readableProvider
      */
-    public function testPrintReadable($input, string $expected)
+    public function testPrintStringReadable($input, string $expected)
     {
         $printer = new Printer();
         $result = $printer->pstr($input, true);
         $this->assertSame($expected, $result);
     }
 
+    /**
+     * @dataProvider readableProvider
+     */
+    public function testPrintReadable($input, string $expected)
+    {
+        $printer = new Printer();
+
+        ob_start();
+        $printer->print($input, true);
+        $result = ob_get_contents();
+        ob_end_clean();
+
+        $this->assertSame($expected, $result);
+    }
+
     public function testPrintResource()
     {
         $file = tmpfile();