Figure: Remove deprecated "timestamp" ("U") parameter, use "Figure.timestamp" instead (deprecated since v0.9.0)

pygmt/helpers/decorators.py

@@ -569,14 +569,11 @@ def new_module(*args, **kwargs):
 
             # timestamp (U) is deprecated since v0.9.0.
             if "U" in kwargs or "timestamp" in kwargs:
-                if "timestamp" in kwargs:
-                    kwargs["U"] = kwargs.pop("timestamp")
                 msg = (
-                    "Parameters 'U' and 'timestamp' are deprecated since v0.9.0 "
-                    "and will be removed in v0.12.0. "
+                    "Parameters 'U' and 'timestamp' are no longer supported since v0.12.0. "
                     "Use Figure.timestamp() instead."
                 )
-                warnings.warn(msg, category=SyntaxWarning, stacklevel=2)
+                raise GMTInvalidInput(msg)
 
             # xshift (X) is deprecated since v0.8.0.
             if "X" in kwargs or "xshift" in kwargs:

pygmt/tests/test_timestamp.py

@@ -2,7 +2,7 @@
 Test Figure.timestamp.
 """
 import pytest
-from pygmt import Figure, config
+from pygmt import Figure
 
 
 @pytest.fixture(scope="module", name="faketime")
@@ -93,38 +93,3 @@ def test_timestamp_text_truncated():
         fig.timestamp(text="0123456789" * 7)
         assert len(record) == 1  # check that only one warning was raised
     return fig
-
-
-@pytest.mark.mpl_image_compare(filename="test_timestamp.png")
-def test_timestamp_deprecated_timestamp(faketime):
-    """
-    Check if the deprecated parameter 'timestamp' works but raises a warning.
-    """
-    fig = Figure()
-    with pytest.warns(expected_warning=SyntaxWarning) as record:
-        with config(FORMAT_TIME_STAMP=faketime):
-            # plot nothing (the data is outside the region) but a timestamp
-            fig.plot(
-                x=0,
-                y=0,
-                style="p",
-                projection="X1c",
-                region=[1, 2, 1, 2],
-                timestamp=True,
-            )
-        assert len(record) == 1  # check that only one warning was raised
-    return fig
-
-
-@pytest.mark.mpl_image_compare(filename="test_timestamp.png")
-def test_timestamp_deprecated_u(faketime):
-    """
-    Check if the deprecated parameter 'U' works but raises a warning.
-    """
-    fig = Figure()
-    with pytest.warns(expected_warning=SyntaxWarning) as record:
-        with config(FORMAT_TIME_STAMP=faketime):
-            # plot nothing (the data is outside the region) but a timestamp
-            fig.plot(x=0, y=0, style="p", projection="X1c", region=[1, 2, 1, 2], U=True)
-        assert len(record) == 1  # check that only one warning was raised
-    return fig