tests.strategies: Ensure to always generate different checksums

swh/web/tests/strategies.py

@@ -39,6 +39,16 @@ storage = tests_data['storage']
 
 # The following strategies exploit the hypothesis capabilities
 
+_generated_checksums = set()
+
+
+def _filter_checksum(cs):
+    if not int.from_bytes(cs, byteorder='little') or \
+            cs in _generated_checksums:
+        return False
+    _generated_checksums.add(cs)
+    return True
+
 
 def _known_swh_object(object_type):
     return sampled_from(tests_data[object_type])
@@ -49,8 +59,7 @@ def sha1():
     Hypothesis strategy returning a valid hexadecimal sha1 value.
     """
     return binary(
-        min_size=20, max_size=20).filter(
-            lambda s: int.from_bytes(s, byteorder='little')).map(hash_to_hex)
+        min_size=20, max_size=20).filter(_filter_checksum).map(hash_to_hex)
 
 
 def invalid_sha1():
@@ -58,8 +67,7 @@ def invalid_sha1():
     Hypothesis strategy returning an invalid sha1 representation.
     """
     return binary(
-        min_size=50, max_size=50).filter(
-            lambda s: int.from_bytes(s, byteorder='little')).map(hash_to_hex)
+        min_size=50, max_size=50).filter(_filter_checksum).map(hash_to_hex)
 
 
 def sha256():
@@ -67,8 +75,7 @@ def sha256():
     Hypothesis strategy returning a valid hexadecimal sha256 value.
     """
     return binary(
-        min_size=32, max_size=32).filter(
-            lambda s: int.from_bytes(s, byteorder='little')).map(hash_to_hex)
+        min_size=32, max_size=32).filter(_filter_checksum).map(hash_to_hex)
 
 
 def content():