Add tests, improve error messages, and use argument checks to simplify code

Author: oscargus

lib/matplotlib/axes/_axes.py

@@ -2336,7 +2336,7 @@ def bar(self, x, height, width=0.8, bottom=None, *, align="center",
         if orientation == 'vertical':
             if y is None:
                 y = 0
-        elif orientation == 'horizontal':
+        else:  # horizontal
             if x is None:
                 x = 0
 
@@ -2345,7 +2345,7 @@ def bar(self, x, height, width=0.8, bottom=None, *, align="center",
                 [("x", x), ("y", height)], kwargs, convert=False)
             if log:
                 self.set_yscale('log', nonpositive='clip')
-        elif orientation == 'horizontal':
+        else:  # horizontal
             self._process_unit_info(
                 [("x", width), ("y", y)], kwargs, convert=False)
             if log:
@@ -2374,7 +2374,7 @@ def bar(self, x, height, width=0.8, bottom=None, *, align="center",
         if orientation == 'vertical':
             tick_label_axis = self.xaxis
             tick_label_position = x
-        elif orientation == 'horizontal':
+        else:  # horizontal
             tick_label_axis = self.yaxis
             tick_label_position = y
 
@@ -2403,15 +2403,15 @@ def bar(self, x, height, width=0.8, bottom=None, *, align="center",
                                     f'and width ({width.dtype}) '
                                     f'are incompatible') from e
                 bottom = y
-            elif orientation == 'horizontal':
+            else:  # horizontal
                 try:
                     bottom = y - height / 2
                 except TypeError as e:
                     raise TypeError(f'the dtypes of parameters y ({y.dtype}) '
                                     f'and height ({height.dtype}) '
                                     f'are incompatible') from e
                 left = x
-        elif align == 'edge':
+        else:  # edge
             left = x
             bottom = y
 
@@ -2431,7 +2431,7 @@ def bar(self, x, height, width=0.8, bottom=None, *, align="center",
             r.get_path()._interpolation_steps = 100
             if orientation == 'vertical':
                 r.sticky_edges.y.append(b)
-            elif orientation == 'horizontal':
+            else:  # horizontal
                 r.sticky_edges.x.append(l)
             self.add_patch(r)
             patches.append(r)
@@ -2442,7 +2442,7 @@ def bar(self, x, height, width=0.8, bottom=None, *, align="center",
                 ex = [l + 0.5 * w for l, w in zip(left, width)]
                 ey = [b + h for b, h in zip(bottom, height)]
 
-            elif orientation == 'horizontal':
+            else:  # horizontal
                 # using list comps rather than arrays to preserve unit info
                 ex = [l + w for l, w in zip(left, width)]
                 ey = [b + 0.5 * h for b, h in zip(bottom, height)]
@@ -2459,7 +2459,7 @@ def bar(self, x, height, width=0.8, bottom=None, *, align="center",
 
         if orientation == 'vertical':
             datavalues = height
-        elif orientation == 'horizontal':
+        else:  # horizontal
             datavalues = width
 
         bar_container = BarContainer(patches, errorbar, datavalues=datavalues,
@@ -2670,46 +2670,47 @@ def sign(x):
             if orientation == "vertical":
                 extrema = max(y0, y1) if dat >= 0 else min(y0, y1)
                 length = abs(y0 - y1)
-            elif orientation == "horizontal":
+            else:  # horizontal
                 extrema = max(x0, x1) if dat >= 0 else min(x0, x1)
                 length = abs(x0 - x1)
 
             if err is None or np.size(err) == 0:
                 endpt = extrema
             elif orientation == "vertical":
                 endpt = err[:, 1].max() if dat >= 0 else err[:, 1].min()
-            elif orientation == "horizontal":
+            else:  # horizontal
                 endpt = err[:, 0].max() if dat >= 0 else err[:, 0].min()
 
             if label_type == "center":
                 value = sign(dat) * length
-            elif label_type == "edge":
+            else:  # edge
                 value = extrema
 
             if label_type == "center":
                 xy = xc, yc
-            elif label_type == "edge" and orientation == "vertical":
-                xy = xc, endpt
-            elif label_type == "edge" and orientation == "horizontal":
-                xy = endpt, yc
+            else:  # edge
+                if orientation == "vertical":
+                    xy = xc, endpt
+                else:  # horizontal
+                    xy = endpt, yc
 
             if orientation == "vertical":
                 y_direction = -1 if y_inverted else 1
                 xytext = 0, y_direction * sign(dat) * padding
-            else:
+            else:  # horizontal
                 x_direction = -1 if x_inverted else 1
                 xytext = x_direction * sign(dat) * padding, 0
 
             if label_type == "center":
                 ha, va = "center", "center"
-            elif label_type == "edge":
+            else:  # edge
                 if orientation == "vertical":
                     ha = 'center'
                     if y_inverted:
                         va = 'top' if dat > 0 else 'bottom'  # also handles NaN
                     else:
                         va = 'top' if dat < 0 else 'bottom'  # also handles NaN
-                elif orientation == "horizontal":
+                else:  # horizontal
                     if x_inverted:
                         ha = 'right' if dat > 0 else 'left'  # also handles NaN
                     else:
@@ -2911,7 +2912,7 @@ def stem(self, *args, linefmt=None, markerfmt=None, basefmt=None, bottom=0,
 
         if orientation == 'vertical':
             locs, heads = self._process_unit_info([("x", locs), ("y", heads)])
-        else:
+        else:  # horizontal
             heads, locs = self._process_unit_info([("x", heads), ("y", locs)])
 
         # defaults for formats
@@ -7796,7 +7797,7 @@ def spy(self, Z, precision=0, marker=None, markersize=None,
         self.title.set_y(1.05)
         if origin == "upper":
             self.xaxis.tick_top()
-        else:
+        else:  # lower
             self.xaxis.tick_bottom()
         self.xaxis.set_ticks_position('both')
         self.xaxis.set_major_locator(

lib/matplotlib/axes/_base.py

@@ -880,7 +880,7 @@ def get_xaxis_transform(self, which='grid'):
             # for cartesian projection, this is top spine
             return self.spines.top.get_spine_transform()
         else:
-            raise ValueError('unknown value for which')
+            raise ValueError(f'unknown value for which: {which!r}')
 
     def get_xaxis_text1_transform(self, pad_points):
         """
@@ -956,7 +956,7 @@ def get_yaxis_transform(self, which='grid'):
             # for cartesian projection, this is top spine
             return self.spines.right.get_spine_transform()
         else:
-            raise ValueError('unknown value for which')
+            raise ValueError(f'unknown value for which: {which!r}')
 
     def get_yaxis_text1_transform(self, pad_points):
         """
@@ -3174,15 +3174,13 @@ def set_axisbelow(self, b):
         --------
         get_axisbelow
         """
+        # Check that b is True, False or 'line'
         self._axisbelow = axisbelow = validate_axisbelow(b)
-        if axisbelow is True:
-            zorder = 0.5
-        elif axisbelow is False:
-            zorder = 2.5
-        elif axisbelow == "line":
-            zorder = 1.5
-        else:
-            raise ValueError("Unexpected axisbelow value")
+        zorder = {
+            True: 0.5,
+            'line': 1.5,
+            False: 2.5,
+        }[axisbelow]
         for axis in self._axis_map.values():
             axis.set_zorder(zorder)
         self.stale = True
@@ -3495,12 +3493,12 @@ def set_xlabel(self, xlabel, fontdict=None, labelpad=None, *,
                    else mpl.rcParams['xaxis.labellocation'])
             _api.check_in_list(('left', 'center', 'right'), loc=loc)
 
-            if loc == 'left':
-                kwargs.update(x=0, horizontalalignment='left')
-            elif loc == 'center':
-                kwargs.update(x=0.5, horizontalalignment='center')
-            elif loc == 'right':
-                kwargs.update(x=1, horizontalalignment='right')
+            x = {
+                'left': 0,
+                'center': 0.5,
+                'right': 1,
+            }[loc]
+            kwargs.update(x=x, horizontalalignment=loc)
 
         return self.xaxis.set_label_text(xlabel, fontdict, **kwargs)
 
@@ -3784,12 +3782,12 @@ def set_ylabel(self, ylabel, fontdict=None, labelpad=None, *,
                    else mpl.rcParams['yaxis.labellocation'])
             _api.check_in_list(('bottom', 'center', 'top'), loc=loc)
 
-            if loc == 'bottom':
-                kwargs.update(y=0, horizontalalignment='left')
-            elif loc == 'center':
-                kwargs.update(y=0.5, horizontalalignment='center')
-            elif loc == 'top':
-                kwargs.update(y=1, horizontalalignment='right')
+            y, ha = {
+                'bottom': (0, 'left'),
+                'center': (0.5, 'center'),
+                'top': (1, 'right')
+            }[loc]
+            kwargs.update(y=y, horizontalalignment=ha)
 
         return self.yaxis.set_label_text(ylabel, fontdict, **kwargs)
 

lib/matplotlib/tests/test_axes.py

@@ -5129,6 +5129,32 @@ def test_axis_errors(err, args, kwargs, match):
         plt.axis(*args, **kwargs)
 
 
+def test_axis_method_errors():
+    ax = plt.gca()
+    with pytest.raises(ValueError, match="unknown value for which: 'foo'"):
+        ax.get_xaxis_transform('foo')
+    with pytest.raises(ValueError, match="unknown value for which: 'foo'"):
+        ax.get_yaxis_transform('foo')
+    with pytest.raises(TypeError, match="Cannot supply both positional and"):
+        ax.set_prop_cycle('foo', label='bar')
+    with pytest.raises(ValueError, match="argument must be among"):
+        ax.set_anchor('foo')
+    with pytest.raises(ValueError, match="scilimits must be a sequence"):
+        ax.ticklabel_format(scilimits=1)
+    with pytest.raises(TypeError, match="Specifying 'loc' is disallowed"):
+        ax.set_xlabel('foo', loc='left', x=1)
+    with pytest.raises(TypeError, match="Specifying 'loc' is disallowed"):
+        ax.set_ylabel('foo', loc='top', y=1)
+    with pytest.raises(TypeError, match="Cannot pass both 'left'"):
+        ax.set_xlim(left=0, xmin=1)
+    with pytest.raises(TypeError, match="Cannot pass both 'right'"):
+        ax.set_xlim(right=0, xmax=1)
+    with pytest.raises(TypeError, match="Cannot pass both 'bottom'"):
+        ax.set_ylim(bottom=0, ymin=1)
+    with pytest.raises(TypeError, match="Cannot pass both 'top'"):
+        ax.set_ylim(top=0, ymax=1)
+
+
 @pytest.mark.parametrize('twin', ('x', 'y'))
 def test_twin_with_aspect(twin):
     fig, ax = plt.subplots()
@@ -7188,6 +7214,7 @@ def test_box_aspect():
     axtwin.plot([12, 344])
 
     ax1.set_box_aspect(1)
+    assert ax1.get_box_aspect() == 1.0
 
     fig2, ax2 = plt.subplots()
     ax2.margins(0)
@@ -7733,6 +7760,60 @@ def test_plot_format_errors(fmt, match, data):
         ax.plot("string", fmt, data=data)
 
 
+def test_plot_format():
+    fig, ax = plt.subplots()
+    line = ax.plot([1, 2, 3], '1.0')
+    assert line[0].get_color() == (1.0, 1.0, 1.0, 1.0)
+    assert line[0].get_marker() == 'None'
+    fig, ax = plt.subplots()
+    line = ax.plot([1, 2, 3], '1')
+    assert line[0].get_marker() == '1'
+    fig, ax = plt.subplots()
+    line = ax.plot([1, 2], [1, 2], '1.0', "1")
+    fig.canvas.draw()
+    assert line[0].get_color() == (1.0, 1.0, 1.0, 1.0)
+    assert ax.get_yticklabels()[0].get_text() == '1'
+    fig, ax = plt.subplots()
+    line = ax.plot([1, 2], [1, 2], '1', "1.0")
+    fig.canvas.draw()
+    assert line[0].get_marker() == '1'
+    assert ax.get_yticklabels()[0].get_text() == '1.0'
+    fig, ax = plt.subplots()
+    line = ax.plot([1, 2, 3], 'k3')
+    assert line[0].get_marker() == '3'
+    assert line[0].get_color() == 'k'
+
+
+def test_automatic_legend():
+    fig, ax = plt.subplots()
+    ax.plot("a", "b", data={"d": 2})
+    leg = ax.legend()
+    fig.canvas.draw()
+    assert leg.get_texts()[0].get_text() == 'a'
+    assert ax.get_yticklabels()[0].get_text() == 'a'
+
+    fig, ax = plt.subplots()
+    ax.plot("a", "b", "c", data={"d": 2})
+    leg = ax.legend()
+    fig.canvas.draw()
+    assert leg.get_texts()[0].get_text() == 'b'
+    assert ax.get_xticklabels()[0].get_text() == 'a'
+    assert ax.get_yticklabels()[0].get_text() == 'b'
+
+
+def test_plot_errors():
+    with pytest.raises(TypeError, match="plot got an unexpected keyword"):
+        plt.plot([1, 2, 3], x=1)
+    with pytest.raises(ValueError, match=r"plot\(\) with multiple groups"):
+        plt.plot([1, 2, 3], [1, 2, 3], [2, 3, 4], [2, 3, 4], label=['1', '2'])
+    with pytest.raises(ValueError, match="x and y must have same first"):
+        plt.plot([1, 2, 3], [1])
+    with pytest.raises(ValueError, match="x and y can be no greater than"):
+        plt.plot(np.ones((2, 2, 2)))
+    with pytest.raises(ValueError, match="Using arbitrary long args with"):
+        plt.plot("a", "b", "c", "d", data={"a": 2})
+
+
 def test_clim():
     ax = plt.figure().add_subplot()
     for plot_method in [