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Add tests for the DNSCache class #728

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Merged
bdraco merged 1 commit into from
Jun 18, 2021
Merged

Add tests for the DNSCache class #728

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102 changes: 102 additions & 0 deletions tests/test_cache.py
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Original file line number Diff line number Diff line change
Expand Up @@ -37,6 +37,38 @@ def test_order(self):
cached_record = cache.get(entry)
assert cached_record == record2

def test_adding_same_record_to_cache_different_ttls(self):
"""We should always get back the last entry we added if there are different TTLs.

This ensures we only have one source of truth for TTLs as a record cannot
be both expired and not expired.
"""
record1 = r.DNSAddress('a', const._TYPE_A, const._CLASS_IN, 1, b'a')
record2 = r.DNSAddress('a', const._TYPE_A, const._CLASS_IN, 10, b'a')
cache = r.DNSCache()
cache.add(record1)
cache.add(record2)
entry = r.DNSEntry(record2)
cached_record = cache.get(entry)
assert cached_record == record2

@unittest.skip('This bug in the implementation needs to be fixed.')
def test_adding_same_record_to_cache_different_ttls(self):
"""Verify we only get one record back.

The last record added should replace the previous since two
records with different ttls are __eq__. This ensures we
only have one source of truth for TTLs as a record cannot
be both expired and not expired.
"""
record1 = r.DNSAddress('a', const._TYPE_A, const._CLASS_IN, 1, b'a')
record2 = r.DNSAddress('a', const._TYPE_A, const._CLASS_IN, 10, b'a')
cache = r.DNSCache()
cache.add(record1)
cache.add(record2)
cached_records = cache.get_all_by_details('a', const._TYPE_A, const._CLASS_IN)
assert cached_records == [record2]

def test_cache_empty_does_not_leak_memory_by_leaving_empty_list(self):
record1 = r.DNSAddress('a', const._TYPE_SOA, const._CLASS_IN, 1, b'a')
record2 = r.DNSAddress('a', const._TYPE_SOA, const._CLASS_IN, 1, b'b')
Expand All @@ -61,3 +93,73 @@ def test_cache_empty_multiple_calls_does_not_throw(self):
cache.remove(record1)
cache.remove(record2)
assert 'a' not in cache.cache


# These functions have been seen in other projects so
# we try to maintain a stable API for all the threadsafe getters
class TestDNSCacheAPI(unittest.TestCase):
def test_get(self):
record1 = r.DNSAddress('a', const._TYPE_A, const._CLASS_IN, 1, b'a')
record2 = r.DNSAddress('a', const._TYPE_A, const._CLASS_IN, 1, b'b')
cache = r.DNSCache()
cache.add_records([record1, record2])
assert cache.get(record1) == record1
assert cache.get(record2) == record2

def test_get_by_details(self):
record1 = r.DNSAddress('a', const._TYPE_A, const._CLASS_IN, 1, b'a')
record2 = r.DNSAddress('a', const._TYPE_A, const._CLASS_IN, 1, b'b')
cache = r.DNSCache()
cache.add_records([record1, record2])
assert cache.get_by_details('a', const._TYPE_A, const._CLASS_IN) == record2

def test_get_all_by_details(self):
record1 = r.DNSAddress('a', const._TYPE_A, const._CLASS_IN, 1, b'a')
record2 = r.DNSAddress('a', const._TYPE_A, const._CLASS_IN, 1, b'b')
cache = r.DNSCache()
cache.add_records([record1, record2])
assert set(cache.get_all_by_details('a', const._TYPE_A, const._CLASS_IN)) == set([record1, record2])

def test_entries_with_server(self):
record1 = r.DNSService(
'irrelevant', const._TYPE_SRV, const._CLASS_IN, const._DNS_HOST_TTL, 0, 0, 85, 'ab'
)
record2 = r.DNSService(
'irrelevant', const._TYPE_SRV, const._CLASS_IN, const._DNS_HOST_TTL, 0, 0, 80, 'ab'
)
cache = r.DNSCache()
cache.add_records([record1, record2])
assert set(cache.entries_with_server('ab')) == set([record1, record2])

def test_entries_with_name(self):
record1 = r.DNSService(
'irrelevant', const._TYPE_SRV, const._CLASS_IN, const._DNS_HOST_TTL, 0, 0, 85, 'ab'
)
record2 = r.DNSService(
'irrelevant', const._TYPE_SRV, const._CLASS_IN, const._DNS_HOST_TTL, 0, 0, 80, 'ab'
)
cache = r.DNSCache()
cache.add_records([record1, record2])
assert set(cache.entries_with_name('irrelevant')) == set([record1, record2])

def test_current_entry_with_name_and_alias(self):
record1 = r.DNSPointer(
'irrelevant', const._TYPE_PTR, const._CLASS_IN, const._DNS_OTHER_TTL, 'x.irrelevant'
)
record2 = r.DNSPointer(
'irrelevant', const._TYPE_PTR, const._CLASS_IN, const._DNS_OTHER_TTL, 'y.irrelevant'
)
cache = r.DNSCache()
cache.add_records([record1, record2])
assert cache.current_entry_with_name_and_alias('irrelevant', 'x.irrelevant') == record1

def test_entries_with_name(self):
record1 = r.DNSService(
'irrelevant', const._TYPE_SRV, const._CLASS_IN, const._DNS_HOST_TTL, 0, 0, 85, 'ab'
)
record2 = r.DNSService(
'irrelevant', const._TYPE_SRV, const._CLASS_IN, const._DNS_HOST_TTL, 0, 0, 80, 'ab'
)
cache = r.DNSCache()
cache.add_records([record1, record2])
assert cache.names() == ['irrelevant']