ripemd160 support + long string hash test

* Note that the long string hash test for RIPEMD160 adds a vector in the
  test. You can verify this vector (for b"a" * 1000000) on the RIPE
  homepage: http://homes.esat.kuleuven.be/~bosselae/ripemd160.html
diff --git a/tests/primitives/test_hashes.py b/tests/primitives/test_hashes.py
index 2f2dd1c..bfb4503 100644
--- a/tests/primitives/test_hashes.py
+++ b/tests/primitives/test_hashes.py
@@ -66,3 +66,13 @@
         only_if=lambda api: api.supports_hash(hashes.SHA512),
         skip_message="Does not support SHA512",
     )
+
+
+class TestRIPEMD160(object):
+    test_RIPEMD160 = generate_base_hash_test(
+        hashes.RIPEMD160,
+        digest_size=20,
+        block_size=64,
+        only_if=lambda api: api.supports_hash(hashes.RIPEMD160),
+        skip_message="Does not support RIPEMD160",
+    )