Add unit tests for Emails class functionality

Week05/test_emails_yasin_soytas.py

@@ -0,0 +1,55 @@
+import pytest
+from emails_yasin_soytas import Emails
+
+
+def test_class_exists():
+    assert Emails is not None
+
+
+def test_is_subclass_of_list():
+    assert issubclass(Emails, list)
+
+
+def test_empty_constructor():
+    e = Emails()
+    assert isinstance(e, list)
+    assert len(e) == 0
+
+
+def test_valid_emails_added():
+    emails = Emails(["[email protected]", "[email protected]"])
+    assert "[email protected]" in emails
+    assert "[email protected]" in emails
+    assert len(emails) == 2
+
+
+def test_emails_lowercase():
+    emails = Emails(["[email protected]"])
+    assert "[email protected]" in emails
+
+
+def test_no_duplicates():
+    emails = Emails(["[email protected]", "[email protected]"])
+    assert len(emails) == 1
+
+
+def test_invalid_emails_not_added():
+    emails = Emails(["testexample.com", 123, None, "hello"])
+    assert len(emails) == 0
+
+
+def test_mixed_input():
+    emails = Emails([
+        "[email protected]",
+        "[email protected]",
+        "invalid",
+        42,
+        "[email protected]"
+    ])
+    assert emails == ["[email protected]", "[email protected]"]
+
+
+
+def test_instance_type():
+    emails = Emails(["[email protected]"])
+    assert isinstance(emails, Emails)