[dashboard] Transfer DNS/mDNS cache from dashboard to CLI to avoid blocking (#10685)

tests/dashboard/status/test_dns.py

@@ -0,0 +1,121 @@
+"""Unit tests for esphome.dashboard.dns module."""
+
+from __future__ import annotations
+
+import time
+from unittest.mock import patch
+
+import pytest
+
+from esphome.dashboard.dns import DNSCache
+
+
+@pytest.fixture
+def dns_cache_fixture() -> DNSCache:
+    """Create a DNSCache instance."""
+    return DNSCache()
+
+
+def test_get_cached_addresses_not_in_cache(dns_cache_fixture: DNSCache) -> None:
+    """Test get_cached_addresses when hostname is not in cache."""
+    now = time.monotonic()
+    result = dns_cache_fixture.get_cached_addresses("unknown.example.com", now)
+    assert result is None
+
+
+def test_get_cached_addresses_expired(dns_cache_fixture: DNSCache) -> None:
+    """Test get_cached_addresses when cache entry is expired."""
+    now = time.monotonic()
+    # Add entry that's already expired
+    dns_cache_fixture._cache["example.com"] = (now - 1, ["192.168.1.10"])
+
+    result = dns_cache_fixture.get_cached_addresses("example.com", now)
+    assert result is None
+    # Expired entry should still be in cache (not removed by get_cached_addresses)
+    assert "example.com" in dns_cache_fixture._cache
+
+
+def test_get_cached_addresses_valid(dns_cache_fixture: DNSCache) -> None:
+    """Test get_cached_addresses with valid cache entry."""
+    now = time.monotonic()
+    # Add entry that expires in 60 seconds
+    dns_cache_fixture._cache["example.com"] = (
+        now + 60,
+        ["192.168.1.10", "192.168.1.11"],
+    )
+
+    result = dns_cache_fixture.get_cached_addresses("example.com", now)
+    assert result == ["192.168.1.10", "192.168.1.11"]
+    # Entry should still be in cache
+    assert "example.com" in dns_cache_fixture._cache
+
+
+def test_get_cached_addresses_hostname_normalization(
+    dns_cache_fixture: DNSCache,
+) -> None:
+    """Test get_cached_addresses normalizes hostname."""
+    now = time.monotonic()
+    # Add entry with lowercase hostname
+    dns_cache_fixture._cache["example.com"] = (now + 60, ["192.168.1.10"])
+
+    # Test with various forms
+    assert dns_cache_fixture.get_cached_addresses("EXAMPLE.COM", now) == [
+        "192.168.1.10"
+    ]
+    assert dns_cache_fixture.get_cached_addresses("example.com.", now) == [
+        "192.168.1.10"
+    ]
+    assert dns_cache_fixture.get_cached_addresses("EXAMPLE.COM.", now) == [
+        "192.168.1.10"
+    ]
+
+
+def test_get_cached_addresses_ipv6(dns_cache_fixture: DNSCache) -> None:
+    """Test get_cached_addresses with IPv6 addresses."""
+    now = time.monotonic()
+    dns_cache_fixture._cache["example.com"] = (now + 60, ["2001:db8::1", "fe80::1"])
+
+    result = dns_cache_fixture.get_cached_addresses("example.com", now)
+    assert result == ["2001:db8::1", "fe80::1"]
+
+
+def test_get_cached_addresses_empty_list(dns_cache_fixture: DNSCache) -> None:
+    """Test get_cached_addresses with empty address list."""
+    now = time.monotonic()
+    dns_cache_fixture._cache["example.com"] = (now + 60, [])
+
+    result = dns_cache_fixture.get_cached_addresses("example.com", now)
+    assert result == []
+
+
+def test_get_cached_addresses_exception_in_cache(dns_cache_fixture: DNSCache) -> None:
+    """Test get_cached_addresses when cache contains an exception."""
+    now = time.monotonic()
+    # Store an exception (from failed resolution)
+    dns_cache_fixture._cache["example.com"] = (now + 60, OSError("Resolution failed"))
+
+    result = dns_cache_fixture.get_cached_addresses("example.com", now)
+    assert result is None  # Should return None for exceptions
+
+
+def test_async_resolve_not_called(dns_cache_fixture: DNSCache) -> None:
+    """Test that get_cached_addresses never calls async_resolve."""
+    now = time.monotonic()
+
+    with patch.object(dns_cache_fixture, "async_resolve") as mock_resolve:
+        # Test non-cached
+        result = dns_cache_fixture.get_cached_addresses("uncached.com", now)
+        assert result is None
+        mock_resolve.assert_not_called()
+
+        # Test expired
+        dns_cache_fixture._cache["expired.com"] = (now - 1, ["192.168.1.10"])
+        result = dns_cache_fixture.get_cached_addresses("expired.com", now)
+        assert result is None
+        mock_resolve.assert_not_called()
+
+        # Test valid
+        dns_cache_fixture._cache["valid.com"] = (now + 60, ["192.168.1.10"])
+        result = dns_cache_fixture.get_cached_addresses("valid.com", now)
+        assert result == ["192.168.1.10"]
+        mock_resolve.assert_not_called()