Fixed database typo and removed unnecessary class identifier.

venv/Lib/site-packages/matplotlib/tests/test_backends_interactive.py

@@ -0,0 +1,227 @@
+import importlib
+import importlib.util
+import json
+import os
+import signal
+import subprocess
+import sys
+import time
+import urllib.request
+
+import pytest
+
+import matplotlib as mpl
+
+
+# Minimal smoke-testing of the backends for which the dependencies are
+# PyPI-installable on CI.  They are not available for all tested Python
+# versions so we don't fail on missing backends.
+
+def _get_testable_interactive_backends():
+    backends = []
+    for deps, backend in [
+            (["cairo", "gi"], "gtk3agg"),
+            (["cairo", "gi"], "gtk3cairo"),
+            (["PyQt5"], "qt5agg"),
+            (["PyQt5", "cairocffi"], "qt5cairo"),
+            (["PySide2"], "qt5agg"),
+            (["PySide2", "cairocffi"], "qt5cairo"),
+            (["tkinter"], "tkagg"),
+            (["wx"], "wx"),
+            (["wx"], "wxagg"),
+            (["matplotlib.backends._macosx"], "macosx"),
+    ]:
+        reason = None
+        missing = [dep for dep in deps if not importlib.util.find_spec(dep)]
+        if sys.platform == "linux" and not os.environ.get("DISPLAY"):
+            reason = "$DISPLAY is unset"
+        elif missing:
+            reason = "{} cannot be imported".format(", ".join(missing))
+        elif backend == 'macosx' and os.environ.get('TF_BUILD'):
+            reason = "macosx backend fails on Azure"
+        if reason:
+            backend = pytest.param(
+                backend,
+                marks=pytest.mark.skip(
+                    reason=f"Skipping {backend} because {reason}"))
+        elif backend.startswith('wx') and sys.platform == 'darwin':
+            # ignore on OSX because that's currently broken (github #16849)
+            backend = pytest.param(
+                backend,
+                marks=pytest.mark.xfail(reason='github #16849'))
+        backends.append(backend)
+    return backends
+
+
+# Using a timer not only allows testing of timers (on other backends), but is
+# also necessary on gtk3 and wx, where a direct call to key_press_event("q")
+# from draw_event causes breakage due to the canvas widget being deleted too
+# early.  Also, gtk3 redefines key_press_event with a different signature, so
+# we directly invoke it from the superclass instead.
+_test_script = """\
+import importlib
+import importlib.util
+import io
+import json
+import sys
+from unittest import TestCase
+
+import matplotlib as mpl
+from matplotlib import pyplot as plt, rcParams
+from matplotlib.backend_bases import FigureCanvasBase
+rcParams.update({
+    "webagg.open_in_browser": False,
+    "webagg.port_retries": 1,
+})
+if len(sys.argv) >= 2:  # Second argument is json-encoded rcParams.
+    rcParams.update(json.loads(sys.argv[1]))
+backend = plt.rcParams["backend"].lower()
+assert_equal = TestCase().assertEqual
+assert_raises = TestCase().assertRaises
+
+if backend.endswith("agg") and not backend.startswith(("gtk3", "web")):
+    # Force interactive framework setup.
+    plt.figure()
+
+    # Check that we cannot switch to a backend using another interactive
+    # framework, but can switch to a backend using cairo instead of agg, or a
+    # non-interactive backend.  In the first case, we use tkagg as the "other"
+    # interactive backend as it is (essentially) guaranteed to be present.
+    # Moreover, don't test switching away from gtk3 (as Gtk.main_level() is
+    # not set up at this point yet) and webagg (which uses no interactive
+    # framework).
+
+    if backend != "tkagg":
+        with assert_raises(ImportError):
+            mpl.use("tkagg", force=True)
+
+    def check_alt_backend(alt_backend):
+        mpl.use(alt_backend, force=True)
+        fig = plt.figure()
+        assert_equal(
+            type(fig.canvas).__module__,
+            "matplotlib.backends.backend_{}".format(alt_backend))
+
+    if importlib.util.find_spec("cairocffi"):
+        check_alt_backend(backend[:-3] + "cairo")
+    check_alt_backend("svg")
+
+mpl.use(backend, force=True)
+
+fig, ax = plt.subplots()
+assert_equal(
+    type(fig.canvas).__module__,
+    "matplotlib.backends.backend_{}".format(backend))
+
+ax.plot([0, 1], [2, 3])
+
+timer = fig.canvas.new_timer(1.)  # Test that floats are cast to int as needed.
+timer.add_callback(FigureCanvasBase.key_press_event, fig.canvas, "q")
+# Trigger quitting upon draw.
+fig.canvas.mpl_connect("draw_event", lambda event: timer.start())
+fig.canvas.mpl_connect("close_event", print)
+
+result = io.BytesIO()
+fig.savefig(result, format='png')
+
+plt.show()
+
+# Ensure that the window is really closed.
+plt.pause(0.5)
+
+# Test that saving works after interactive window is closed, but the figure is
+# not deleted.
+result_after = io.BytesIO()
+fig.savefig(result_after, format='png')
+
+if not backend.startswith('qt5') and sys.platform == 'darwin':
+    # FIXME: This should be enabled everywhere once Qt5 is fixed on macOS to
+    # not resize incorrectly.
+    assert_equal(result.getvalue(), result_after.getvalue())
+"""
+_test_timeout = 10  # Empirically, 1s is not enough on Travis.
+
+
+@pytest.mark.parametrize("backend", _get_testable_interactive_backends())
+@pytest.mark.parametrize("toolbar", ["toolbar2", "toolmanager"])
+@pytest.mark.flaky(reruns=3)
+def test_interactive_backend(backend, toolbar):
+    if backend == "macosx":
+        if toolbar == "toolmanager":
+            pytest.skip("toolmanager is not implemented for macosx.")
+        if toolbar == "toolbar2" and os.environ.get('TRAVIS'):
+            # See https://github.com/matplotlib/matplotlib/issues/18213
+            pytest.skip("toolbar2 for macosx is buggy on Travis.")
+
+    proc = subprocess.run(
+        [sys.executable, "-c", _test_script,
+         json.dumps({"toolbar": toolbar})],
+        env={**os.environ, "MPLBACKEND": backend, "SOURCE_DATE_EPOCH": "0"},
+        timeout=_test_timeout,
+        stdout=subprocess.PIPE, universal_newlines=True)
+    if proc.returncode:
+        pytest.fail("The subprocess returned with non-zero exit status "
+                    f"{proc.returncode}.")
+    assert proc.stdout.count("CloseEvent") == 1
+
+
+@pytest.mark.skipif('TF_BUILD' in os.environ,
+                    reason="this test fails an azure for unknown reasons")
+@pytest.mark.skipif(os.name == "nt", reason="Cannot send SIGINT on Windows.")
+def test_webagg():
+    pytest.importorskip("tornado")
+    proc = subprocess.Popen([sys.executable, "-c", _test_script],
+                            env={**os.environ, "MPLBACKEND": "webagg",
+                                 "SOURCE_DATE_EPOCH": "0"})
+    url = "http://{}:{}".format(
+        mpl.rcParams["webagg.address"], mpl.rcParams["webagg.port"])
+    timeout = time.perf_counter() + _test_timeout
+    while True:
+        try:
+            retcode = proc.poll()
+            # check that the subprocess for the server is not dead
+            assert retcode is None
+            conn = urllib.request.urlopen(url)
+            break
+        except urllib.error.URLError:
+            if time.perf_counter() > timeout:
+                pytest.fail("Failed to connect to the webagg server.")
+            else:
+                continue
+    conn.close()
+    proc.send_signal(signal.SIGINT)
+    assert proc.wait(timeout=_test_timeout) == 0
+
+
+@pytest.mark.skipif(sys.platform != "linux", reason="this a linux-only test")
+@pytest.mark.backend('Qt5Agg', skip_on_importerror=True)
+def test_lazy_linux_headless():
+    test_script = """
+import os
+import sys
+
+# make it look headless
+del os.environ['DISPLAY']
+
+# we should fast-track to Agg
+import matplotlib.pyplot as plt
+plt.get_backend() == 'agg'
+assert 'PyQt5' not in sys.modules
+
+# make sure we really have pyqt installed
+import PyQt5
+assert 'PyQt5' in sys.modules
+
+# try to switch and make sure we fail with ImportError
+try:
+    plt.switch_backend('qt5agg')
+except ImportError:
+    ...
+else:
+    sys.exit(1)
+
+"""
+    proc = subprocess.run([sys.executable, "-c", test_script])
+    if proc.returncode:
+        pytest.fail("The subprocess returned with non-zero exit status "
+                    f"{proc.returncode}.")