HW8 Complete

matPlotLib/env/lib/python3.7/site-packages/matplotlib/testing/determinism.py

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+"""
+Provides utilities to test output reproducibility.
+"""
+
+import os
+import re
+import subprocess
+import sys
+
+import pytest
+
+import matplotlib
+from matplotlib import pyplot as plt
+
+
+def _determinism_save(objects='mhi', format="pdf", usetex=False):
+    # save current value of SOURCE_DATE_EPOCH and set it
+    # to a constant value, so that time difference is not
+    # taken into account
+    sde = os.environ.pop('SOURCE_DATE_EPOCH', None)
+    os.environ['SOURCE_DATE_EPOCH'] = "946684800"
+
+    matplotlib.rcParams['text.usetex'] = usetex
+
+    fig = plt.figure()
+
+    if 'm' in objects:
+        # use different markers...
+        ax1 = fig.add_subplot(1, 6, 1)
+        x = range(10)
+        ax1.plot(x, [1] * 10, marker='D')
+        ax1.plot(x, [2] * 10, marker='x')
+        ax1.plot(x, [3] * 10, marker='^')
+        ax1.plot(x, [4] * 10, marker='H')
+        ax1.plot(x, [5] * 10, marker='v')
+
+    if 'h' in objects:
+        # also use different hatch patterns
+        ax2 = fig.add_subplot(1, 6, 2)
+        bars = (ax2.bar(range(1, 5), range(1, 5)) +
+                ax2.bar(range(1, 5), [6] * 4, bottom=range(1, 5)))
+        ax2.set_xticks([1.5, 2.5, 3.5, 4.5])
+
+        patterns = ('-', '+', 'x', '\\', '*', 'o', 'O', '.')
+        for bar, pattern in zip(bars, patterns):
+            bar.set_hatch(pattern)
+
+    if 'i' in objects:
+        # also use different images
+        A = [[1, 2, 3], [2, 3, 1], [3, 1, 2]]
+        fig.add_subplot(1, 6, 3).imshow(A, interpolation='nearest')
+        A = [[1, 3, 2], [1, 2, 3], [3, 1, 2]]
+        fig.add_subplot(1, 6, 4).imshow(A, interpolation='bilinear')
+        A = [[2, 3, 1], [1, 2, 3], [2, 1, 3]]
+        fig.add_subplot(1, 6, 5).imshow(A, interpolation='bicubic')
+
+    x = range(5)
+    fig.add_subplot(1, 6, 6).plot(x, x)
+
+    stdout = getattr(sys.stdout, 'buffer', sys.stdout)
+    fig.savefig(stdout, format=format)
+
+    # Restores SOURCE_DATE_EPOCH
+    if sde is None:
+        os.environ.pop('SOURCE_DATE_EPOCH', None)
+    else:
+        os.environ['SOURCE_DATE_EPOCH'] = sde
+
+
+def _determinism_check(objects='mhi', format="pdf", usetex=False):
+    """
+    Output three times the same graphs and checks that the outputs are exactly
+    the same.
+
+    Parameters
+    ----------
+    objects : str
+        contains characters corresponding to objects to be included in the test
+        document: 'm' for markers, 'h' for hatch patterns, 'i' for images. The
+        default value is "mhi", so that the test includes all these objects.
+    format : str
+        format string. The default value is "pdf".
+    """
+    plots = []
+    for i in range(3):
+        result = subprocess.check_output([
+            sys.executable, '-R', '-c',
+            'import matplotlib; '
+            'matplotlib._called_from_pytest = True; '
+            'matplotlib.use(%r); '
+            'from matplotlib.testing.determinism import _determinism_save;'
+            '_determinism_save(%r, %r, %r)'
+            % (format, objects, format, usetex)])
+        plots.append(result)
+    for p in plots[1:]:
+        if usetex:
+            if p != plots[0]:
+                pytest.skip("failed, maybe due to ghostscript timestamps")
+        else:
+            assert p == plots[0]
+
+
+def _determinism_source_date_epoch(format, string, keyword=b"CreationDate"):
+    """
+    Test SOURCE_DATE_EPOCH support. Output a document with the environment
+    variable SOURCE_DATE_EPOCH set to 2000-01-01 00:00 UTC and check that the
+    document contains the timestamp that corresponds to this date (given as an
+    argument).
+
+    Parameters
+    ----------
+    format : str
+        format string, such as "pdf".
+    string : str
+        timestamp string for 2000-01-01 00:00 UTC.
+    keyword : bytes
+        a string to look at when searching for the timestamp in the document
+        (used in case the test fails).
+    """
+    buff = subprocess.check_output([
+        sys.executable, '-R', '-c',
+        'import matplotlib; '
+        'matplotlib._called_from_pytest = True; '
+        'matplotlib.use(%r); '
+        'from matplotlib.testing.determinism import _determinism_save;'
+        '_determinism_save(%r, %r)'
+        % (format, "", format)])
+    find_keyword = re.compile(b".*" + keyword + b".*")
+    key = find_keyword.search(buff)
+    if key:
+        print(key.group())
+    else:
+        print("Timestamp keyword (%s) not found!" % keyword)
+    assert string in buff