Add property based test for nsec3hash utility

Check the correctness of NSEC3 hash generation by generating random
combinations of name, salt, and iterations and comparing the outputs
of the nsec3hash tool against the dnspython nsec3_hash function
for the same inputs.

(cherry picked from commit e263df8848)

bin/tests/system/tools/tests_tools_nsec3hash.py

@@ -15,6 +15,12 @@ import subprocess
 import pytest
 
 import isctest
+from isctest.hypothesis.strategies import dns_names
+
+from hypothesis import strategies, given, settings
+
+from dns.dnssectypes import NSEC3Hash
+import dns.dnssec
 
 NSEC3HASH = os.environ.get("NSEC3HASH")
 
@@ -120,3 +126,51 @@ def test_nsec3_missing_args(args):
 def test_nsec3_bad_option():
     with pytest.raises(subprocess.CalledProcessError):
         isctest.run.cmd([NSEC3HASH, "-?"])
+
+
+@given(
+    domain=dns_names(),
+    it=strategies.integers(min_value=0, max_value=65535),
+    salt_bytes=strategies.binary(min_size=0, max_size=255),
+)
+def test_nsec3hash_acceptable_values(domain, it, salt_bytes) -> None:
+    if not salt_bytes:
+        salt_text = "-"
+    else:
+        salt_text = salt_bytes.hex()
+    # calculate the hash using dnspython:
+    hash1 = dns.dnssec.nsec3_hash(
+        domain, salt=salt_bytes, iterations=it, algorithm=NSEC3Hash.SHA1
+    )
+
+    # calculate the hash using nsec3hash:
+    output = isctest.run.cmd(
+        [NSEC3HASH, salt_text, "1", str(it), str(domain)]
+    ).stdout.decode("ascii")
+    hash2 = output.partition(" ")[0]
+
+    assert hash1 == hash2
+
+
+@settings(max_examples=5)
+@given(
+    domain=dns_names(),
+    it=strategies.integers(min_value=0, max_value=65535),
+    salt_bytes=strategies.binary(min_size=256),
+)
+def test_nsec3hash_salt_too_long(domain, it, salt_bytes) -> None:
+    salt_text = salt_bytes.hex()
+    with pytest.raises(subprocess.CalledProcessError):
+        isctest.run.cmd([NSEC3HASH, salt_text, "1", str(it), str(domain)])
+
+
+@settings(max_examples=5)
+@given(
+    domain=dns_names(),
+    it=strategies.integers(min_value=65536),
+    salt_bytes=strategies.binary(min_size=0, max_size=255),
+)
+def test_nsec3hash_too_many_iterations(domain, it, salt_bytes) -> None:
+    salt_text = salt_bytes.hex()
+    with pytest.raises(subprocess.CalledProcessError):
+        isctest.run.cmd([NSEC3HASH, salt_text, "1", str(it), str(domain)])