diff --git a/requirements.testing.txt b/requirements.testing.txt
new file mode 100644
index 0000000..466a229
--- /dev/null
+++ b/requirements.testing.txt
@@ -0,0 +1,3 @@
+pytest
+pytest-cov
+pytest-runner
diff --git a/tests/test_pki_builder.py b/tests/test_pki_builder.py
new file mode 100644
index 0000000..5b983b1
--- /dev/null
+++ b/tests/test_pki_builder.py
@@ -0,0 +1,50 @@
+import unittest
+import iyzipay
+
+class PKIBuilderTest(unittest.TestCase):
+
+    def test_append_when_value_available(self):
+        pki_builder = iyzipay.PKIBuilder('')
+        pki_builder.append('key', 'value')
+        self.assertEqual(pki_builder.get_request_string(), '[key=value]')
+
+    def test_append_when_value_not_available(self):
+        pki_builder = iyzipay.PKIBuilder('')
+        pki_builder.append('key')
+        self.assertEqual(pki_builder.get_request_string(), '[]')
+
+    def test_append_when_value_empty(self):
+        pki_builder = iyzipay.PKIBuilder('')
+        pki_builder.append('key', '')
+        self.assertEqual(pki_builder.get_request_string(), '[]')
+
+    def test_append_price_when_value_available(self):
+        pki_builder = iyzipay.PKIBuilder('')
+        pki_builder.append_price('price', 100)
+        self.assertEqual(pki_builder.get_request_string(), '[price=100.0]')
+
+    def test_append_price_when_value_not_available(self):
+        pki_builder = iyzipay.PKIBuilder('')
+        pki_builder.append_price('price')
+        self.assertEqual(pki_builder.get_request_string(), '[]')
+
+    def test_append_price_when_value_empty(self):
+        pki_builder = iyzipay.PKIBuilder('')
+        pki_builder.append_price('price', '')
+        self.assertEqual(pki_builder.get_request_string(), '[]')
+
+    def test_append_array_when_value_available(self):
+        enabledInstallments = ['2', '3', '6', '9']
+        pki_builder = iyzipay.PKIBuilder('')
+        pki_builder.append_array('data', enabledInstallments)
+        self.assertEqual(pki_builder.get_request_string(), '[data=[2, 3, 6, 9]]')
+
+    def test_append_array_when_value_not_available(self):
+        pki_builder = iyzipay.PKIBuilder('')
+        pki_builder.append_array('data')
+        self.assertEqual(pki_builder.get_request_string(), '[]')
+
+    def test_append_array_when_value_empty(self):
+        pki_builder = iyzipay.PKIBuilder('')
+        pki_builder.append_array('data', [])
+        self.assertEqual(pki_builder.get_request_string(), '[]')