diff --git a/tests/test_release_note_generator.py b/tests/test_release_note_generator.py
new file mode 100644
index 0000000..bd21da8
--- /dev/null
+++ b/tests/test_release_note_generator.py
@@ -0,0 +1,168 @@
+import sys
+from pathlib import Path
+from textwrap import dedent
+
+import pytest
+
+sys.path.insert(0, str(Path(__file__).resolve().parents[1]))
+
+from release_note_generator import DataType, parse_change_log, print_change_log
+
+
+def parse(diff):
+    return parse_change_log(dedent(diff).lstrip())
+
+
+def test_tracks_added_removed_and_updated_datatypes():
+    change_log = parse(
+        """
+        diff --git a/files.stone b/files.stone
+        index 1111111..2222222 100644
+        --- a/files.stone
+        +++ b/files.stone
+        @@ -1,7 +1,9 @@
+         namespace files
+         route existing_route(ExistingArg, ExistingResult, ExistingError)
+        +route added_route(AddedArg, AddedResult, AddedError)
+        -route removed_route(RemovedArg, RemovedResult, RemovedError)
+         struct User
+        -    old_field String
+        +    new_field String
+         struct ExistingStruct
+        +struct AddedStruct
+        -struct RemovedStruct
+         union ExistingUnion
+        +union AddedUnion
+        -union RemovedUnion
+        """
+    )
+
+    assert len(change_log.ns_changes) == 1
+
+    ns_change = change_log.ns_changes[0]
+
+    assert ns_change.file_name == "files"
+    assert ns_change.added_routes == ["added_route"]
+    assert ns_change.removed_routes == ["removed_route"]
+
+    assert ns_change.added_structs == ["AddedStruct"]
+    assert ns_change.removed_structs == ["RemovedStruct"]
+
+    assert ns_change.added_unions == ["AddedUnion"]
+    assert ns_change.removed_unions == ["RemovedUnion"]
+
+    assert (DataType.STRUCT, "User") in ns_change.updated_datatypes
+
+
+def test_tracks_plain_route_deprecation():
+    change_log = parse(
+        """
+        diff --git a/files.stone b/files.stone
+        index 1111111..2222222 100644
+        --- a/files.stone
+        +++ b/files.stone
+        @@ -1,3 +1,3 @@
+         namespace files
+        -route create_folder(CreateFolderArg, FolderMetadata, CreateFolderError)
+        +route create_folder(CreateFolderArg, FolderMetadata, CreateFolderError) deprecated
+         route list_folder(ListFolderArg, ListFolderResult, ListFolderError)
+        """
+    )
+
+    ns_change = change_log.ns_changes[0]
+
+    assert ns_change.added_routes == []
+    assert ns_change.removed_routes == []
+    assert ns_change.deprecated_routes == ["create_folder"]
+
+
+def test_tracks_replacement_route_deprecation():
+    change_log = parse(
+        """
+        diff --git a/files.stone b/files.stone
+        index 1111111..2222222 100644
+        --- a/files.stone
+        +++ b/files.stone
+        @@ -1,3 +1,3 @@
+         namespace files
+        -route get_shared_links(GetSharedLinksArg, GetSharedLinksResult, GetSharedLinksError)
+        +route get_shared_links(GetSharedLinksArg, GetSharedLinksResult, GetSharedLinksError) deprecated by list_shared_links
+         route list_shared_links(ListSharedLinksArg, ListSharedLinksResult, ListSharedLinksError)
+        """
+    )
+
+    ns_change = change_log.ns_changes[0]
+
+    assert ns_change.added_routes == []
+    assert ns_change.removed_routes == []
+    assert ns_change.deprecated_routes == [
+        "get_shared_links replaced by list_shared_links"
+    ]
+
+
+def test_does_not_report_new_deprecated_route_as_deprecated_change():
+    change_log = parse(
+        """
+        diff --git a/files.stone b/files.stone
+        index 1111111..2222222 100644
+        --- a/files.stone
+        +++ b/files.stone
+        @@ -1,2 +1,3 @@
+         namespace files
+         route existing_route(ExistingArg, ExistingResult, ExistingError)
+        +route new_deprecated_route(NewArg, NewResult, NewError) deprecated
+        """
+    )
+
+    ns_change = change_log.ns_changes[0]
+
+    assert ns_change.added_routes == ["new_deprecated_route"]
+    assert ns_change.deprecated_routes == []
+
+
+def test_tracks_added_and_removed_namespaces():
+    change_log = parse(
+        """
+        diff --git a/new_namespace.stone b/new_namespace.stone
+        new file mode 100644
+        index 0000000..1111111
+        --- /dev/null
+        +++ b/new_namespace.stone
+        @@ -0,0 +1,2 @@
+        +namespace new_namespace
+        +route added_route(AddedArg, AddedResult, AddedError)
+        diff --git a/old_namespace.stone b/old_namespace.stone
+        deleted file mode 100644
+        index 1111111..0000000
+        --- a/old_namespace.stone
+        +++ /dev/null
+        @@ -1,2 +0,0 @@
+        -namespace old_namespace
+        -route removed_route(RemovedArg, RemovedResult, RemovedError)
+        """
+    )
+
+    assert change_log.added_nses == ["new_namespace"]
+    assert change_log.removed_nses == ["old_namespace"]
+
+
+def test_print_change_log_labels_removed_namespaces_correctly(capsys):
+    change_log = parse(
+        """
+        diff --git a/legacy.stone b/legacy.stone
+        deleted file mode 100644
+        index 1111111..0000000
+        --- a/legacy.stone
+        +++ /dev/null
+        @@ -1,2 +0,0 @@
+        -namespace legacy
+        -route old_route(OldArg, OldResult, OldError)
+        """
+    )
+
+    print_change_log(change_log)
+
+    output = capsys.readouterr().out
+
+    assert "Remove legacy namespace" in output
+    assert "Add legacy namespace" not in output