diff --git a/CHANGELOG.md b/CHANGELOG.md
index 742ac45c..2358c648 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,12 +11,17 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 - Make `get_collection` raise if `collection_id` is empty ([#809](https://github.com/stac-utils/pystac-client/pull/809))
 
+### Added
+
+- Add comprehensive test coverage for ConformanceClasses enum ([#834](https://github.com/stac-utils/pystac-client/pull/834))
+
 ### Documentation
 
 - Update contributing guide to consistently use `uv` workflow ([#822](https://github.com/stac-utils/pystac-client/pull/822))
 - Fix format script to use `ruff-format` instead of deprecated `black` hook ([#822](https://github.com/stac-utils/pystac-client/pull/822))
 - Add "How to..." section to usage documentation with latest datetime search across multiple collections example ([#823](https://github.com/stac-utils/pystac-client/pull/823))
 
+
 ## [v0.9.0] - 2025-07-17
 
 ### Added
diff --git a/tests/test_conformance.py b/tests/test_conformance.py
new file mode 100644
index 00000000..d2dc873d
--- /dev/null
+++ b/tests/test_conformance.py
@@ -0,0 +1,32 @@
+import pytest
+
+from pystac_client.conformance import ConformanceClasses
+
+
+class TestConformanceClasses:
+    def test_get_by_name_raises_for_invalid_names(self) -> None:
+        """Test get_by_name raises ValueError for invalid conformance class names."""
+        with pytest.raises(ValueError, match="Invalid conformance class 'invalid'"):
+            ConformanceClasses.get_by_name("invalid")
+
+        with pytest.raises(ValueError, match="Invalid conformance class 'nonexistent'"):
+            ConformanceClasses.get_by_name("nonexistent")
+
+        with pytest.raises(ValueError, match="Invalid conformance class ''"):
+            ConformanceClasses.get_by_name("")
+
+    def test_get_by_name_valid(self) -> None:
+        """Test get_by_name with valid conformance class names."""
+        assert ConformanceClasses.get_by_name("core") == ConformanceClasses.CORE
+        assert ConformanceClasses.get_by_name("CORE") == ConformanceClasses.CORE
+
+    def test_valid_uri_property(self) -> None:
+        """Test valid_uri property returns correct URI pattern."""
+        assert (
+            ConformanceClasses.CORE.valid_uri == "https://api.stacspec.org/v1.0.*/core"
+        )
+
+    def test_pattern_property(self) -> None:
+        """Test pattern property returns compiled regex."""
+        core_pattern = ConformanceClasses.CORE.pattern
+        assert core_pattern.match("https://api.stacspec.org/v1.0.0/core")