Unit tests for Blockchain.verify_header

electrum/tests/test_blockchain.py

@@ -339,3 +339,37 @@ def test_doing_multiple_swaps_after_single_new_header(self):
 
         for b in (chain_u, chain_l, chain_z):
             self.assertTrue(all([b.can_connect(b.read_header(i), False) for i in range(b.height())]))
+
+
+class TestVerifyHeader(SequentialTestCase):
+
+    # Data for Bitcoin block header #100.
+    valid_header = "0100000095194b8567fe2e8bbda931afd01a7acd399b9325cb54683e64129bcd00000000660802c98f18fd34fd16d61c63cf447568370124ac5f3be626c2e1c3c9f0052d19a76949ffff001d33f3c25d"
+    target = Blockchain.bits_to_target(0x1d00ffff)
+    prev_hash = "00000000cd9b12643e6854cb25939b39cd7a1ad0af31a9bd8b2efe67854b1995"
+
+    def setUp(self):
+        super().setUp()
+        self.header = deserialize_header(bfh(self.valid_header), 100)
+
+    def test_valid_header(self):
+        Blockchain.verify_header(self.header, self.prev_hash, self.target)
+
+    def test_expected_hash_mismatch(self):
+        with self.assertRaises(Exception):
+            Blockchain.verify_header(self.header, self.prev_hash, self.target,
+                                     expected_header_hash="foo")
+
+    def test_prev_hash_mismatch(self):
+        with self.assertRaises(Exception):
+            Blockchain.verify_header(self.header, "foo", self.target)
+
+    def test_target_mismatch(self):
+        with self.assertRaises(Exception):
+            other_target = Blockchain.bits_to_target(0x1d00eeee)
+            Blockchain.verify_header(self.header, self.prev_hash, other_target)
+
+    def test_insufficient_pow(self):
+        with self.assertRaises(Exception):
+            self.header["nonce"] = 42
+            Blockchain.verify_header(self.header, self.prev_hash, self.target)