is_valid_email rejects real addresses

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Final diff

diff --git a/test_validate.py b/test_validate.py
index 722913d..801b73c 100644
--- a/test_validate.py
+++ b/test_validate.py
@@ -7,3 +7,67 @@ def test_simple_address():
 
 def test_missing_at():
     assert not is_valid_email("userexample.com")
+
+
+def test_dot_and_plus_in_local_part():
+    assert is_valid_email("first.last@example.com")
+    assert is_valid_email("user+tag@example.com")
+
+
+def test_uppercase():
+    assert is_valid_email("USER@EXAMPLE.COM")
+
+
+def test_multi_part_domain():
+    assert is_valid_email("a@mail.example.co.uk")
+
+
+def test_no_dot_in_domain():
+    assert not is_valid_email("user@example")
+    assert not is_valid_email("a@example")
+
+
+def test_space():
+    assert not is_valid_email("a b@example.com")
+    assert not is_valid_email("user name@example.com")
+
+
+def test_empty_local_part():
+    assert not is_valid_email("@example.com")
+
+
+def test_empty_domain_label():
+    assert not is_valid_email("a@.com")
+
+
+def test_one_letter_tld():
+    assert not is_valid_email("a@example.c")
+
+
+def test_trailing_newline():
+    assert not is_valid_email("user@example.com\n")
+
+
+def test_leading_newline_and_tab():
+    assert not is_valid_email("\nuser@example.com")
+    assert not is_valid_email("user@example.com\t")
+
+
+def test_hyphen_in_domain_label():
+    assert is_valid_email("a@x-y.com")
+    assert not is_valid_email("a@-x.com")
+    assert not is_valid_email("a@x-.com")
+
+
+def test_invalid_domain_characters():
+    assert not is_valid_email("user@exa_mple.com")
+    assert not is_valid_email("user@example.com.")
+    assert not is_valid_email("user@example.c0m")
+
+
+def test_multiple_at_signs():
+    assert not is_valid_email("a@b@c.com")
+
+
+def test_non_ascii_rejected():
+    assert not is_valid_email("ü@example.com")
diff --git a/validate.py b/validate.py
index 1141430..6994d90 100644
--- a/validate.py
+++ b/validate.py
@@ -1,7 +1,9 @@
 import re
 
-_EMAIL = re.compile(r"^[a-z0-9]+@[a-z0-9]+\.[a-z]{2,}$")
+_EMAIL = re.compile(
+    r"[A-Za-z0-9._%+-]+@(?:[A-Za-z0-9](?:[A-Za-z0-9-]*[A-Za-z0-9])?\.)+[A-Za-z]{2,}"
+)
 
 
 def is_valid_email(address: str) -> bool:
-    return _EMAIL.match(address) is not None
+    return _EMAIL.fullmatch(address) is not None