Add sign and verify capability to Identity

tests/test_identity.py

@@ -199,3 +199,56 @@ def test_eq_other(identity: Identity) -> None:
 
     with pytest.raises(TypeError):
         assert identity == 1
+
+
+def test_sign_nokey() -> None:
+    """Test if Identity.sign() fails if the identity doesn’t have a signing key available"""
+
+    identity_str = '@test.bcz76z52y5dlpohtkmpuj3jsdcvfmebzpcgfmtmhu4u7hlexzreya'
+    identity = Identity.from_address(identity_str)
+
+    with pytest.raises(TypeError):
+        identity.sign('test data')
+
+
+@pytest.mark.id_key_seed(TEST_SEED)
+@pytest.mark.id_name('test')
+def test_sign(identity: Identity) -> None:
+    """Test if Identity.sign() works as expected"""
+
+    assert (
+        identity.sign('test data')
+        == 'b6gyis42cvdfhsp7xx3jb4773ebbqoq4zhdo4pyeitskefrfkkzxwdkwjkjpq2oyglpngx4tpzzezeedp7eb'
+        'x4i3vkpq7wj6odjinacy'
+    )
+
+
+@pytest.mark.id_key_seed(TEST_SEED)
+@pytest.mark.id_name('test')
+def test_verify(identity: Identity) -> None:
+    """Test if Identity.verify works as expected"""
+
+    assert (
+        identity.verify(
+            'test data',
+            'b6gyis42cvdfhsp7xx3jb4773ebbqoq4zhdo4pyeitskefrfkkzxwdkwjkjpq2oyglpngx4tpzzezeedp7eb'
+            'x4i3vkpq7wj6odjinacy',
+        )
+        is True
+    )
+    assert (
+        identity.verify(
+            'test date',
+            'b6gyis42cvdfhsp7xx3jb4773ebbqoq4zhdo4pyeitskefrfkkzxwdkwjkjpq2oyglpngx4tpzzezeedp7eb'
+            'x4i3vkpq7wj6odjinacy',
+        )
+        is False
+    )
+    assert (
+        identity.verify(
+            'test data',
+            'b6gyis42cvdfhsp7xx3jb4773ebbqoq4zhdo4pyeitskefrfkkzxwdkwjkjpq2oyglpngx4tpzzezeedp7eb'
+            'x4i3vkpq7wj6odjinacq',
+        )
+        is False
+    )