Add tests to assure copyright text is the same (listed in 4 places)

tests/metadata_test.py

@@ -0,0 +1,24 @@
+"""Ensure the metadata is updated and valid."""
+from utils import REPO_PATH
+import becquerel as bq
+
+COPYRIGHT = (REPO_PATH / "COPYRIGHT.txt").read_text().strip("\n")
+
+
+def test_copyright_in_license():
+    license = (REPO_PATH / "LICENSE.txt").read_text()
+    copyright_in_license = (
+        license.split("*** Copyright Notice ***")[-1]
+        .split("*** License Agreement ***")[0]
+        .strip("\n")
+    )
+    assert COPYRIGHT == copyright_in_license
+
+
+def test_copyright_in_readme():
+    readme = (REPO_PATH / "README.md").read_text().strip("\n")
+    assert readme.endswith(COPYRIGHT)
+
+
+def test_copyright_in_metadata():
+    assert bq.__metadata__.__copyright__.strip("\n") == COPYRIGHT