diff --git a/ddb/ddb_20180619.fits.gz b/ddb/ddb_20180619.fits.gz
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Binary files /dev/null and b/ddb/ddb_20180619.fits.gz differ
diff --git a/tests/test_ddb.py b/tests/test_ddb.py
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+++ b/tests/test_ddb.py
@@ -0,0 +1,20 @@
+# standard library
+from pathlib import Path
+
+
+# dependencies
+from astropy.io import fits
+from pytest import mark
+
+
+# constants
+DDB_DIR = Path(__file__).parents[1] / "ddb"
+DDB_ALL = list(DDB_DIR.glob("*.fits.gz"))
+
+
+# test functions
+@mark.parametrize("ddb", DDB_ALL)
+def test_open(ddb: Path) -> None:
+    """Test existence and opening of DDBs."""
+    with fits.open(ddb):
+        pass