push sheeet

pkgs/development/python-modules/invisible-watermark/tests/python/default.nix

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+{
+  image,
+  invisible-watermark,
+  opencv4,
+  python,
+  runCommand,
+  stdenvNoCC,
+}:
+
+# This test checks if the python code shown in the README works correctly
+
+let
+  message = "fnörd1";
+  method = "dwtDct";
+
+  pythonWithPackages = python.withPackages (_: [
+    invisible-watermark
+    opencv4
+  ]);
+  pythonInterpreter = pythonWithPackages.interpreter;
+
+  encode = stdenvNoCC.mkDerivation {
+    name = "encode";
+    realBuilder = pythonInterpreter;
+    args = [ ./encode.py ];
+    inherit image message method;
+  };
+
+  decode = stdenvNoCC.mkDerivation {
+    name = "decode";
+    realBuilder = pythonInterpreter;
+    args = [ ./decode.py ];
+    inherit method;
+    image = "${encode}/test_wm.png";
+    num_bits = (builtins.stringLength message) * 8;
+  };
+in
+runCommand "invisible-watermark-test-python" { } ''
+  decoded_message="$(cat '${decode}')"
+  if [ '${message}' != "$decoded_message" ]; then
+    echo "invisible-watermark did not decode the watermark correctly."
+    echo "The original message was ${message} but the decoded message was $decoded_message."
+    exit 1
+  fi
+  touch "$out"
+''