Test some untested Locator code and code improvements

oscargus · oscargus · commit 09ab594011cd · 2023-08-10T21:31:49.000+02:00
diff --git a/lib/matplotlib/tests/test_ticker.py b/lib/matplotlib/tests/test_ticker.py
@@ -38,13 +38,38 @@ def test_integer(self, vmin, vmax, steps, expected):
         loc = mticker.MaxNLocator(nbins=5, integer=True, steps=steps)
         assert_almost_equal(loc.tick_values(vmin, vmax), expected)
 
+    @pytest.mark.parametrize('kwargs, errortype, match', [
+        ({'foo': 0}, TypeError,
+         re.escape("set_params() got an unexpected keyword argument 'foo'")),
+        ({'steps': [2, 1]}, ValueError, "steps argument must be an increasing"),
+        ({'steps': 2}, ValueError, "steps argument must be an increasing"),
+        ({'steps': [2, 11]}, ValueError, "steps argument must be an increasing"),
+    ])
+    def test_errors(self, kwargs, errortype, match):
+        with pytest.raises(errortype, match=match):
+            mticker.MaxNLocator(**kwargs)
+
+    @pytest.mark.parametrize('steps, result', [
+        ([1, 2, 10], [1, 2, 10]),
+        ([2, 10], [1, 2, 10]),
+        ([1, 2], [1, 2, 10]),
+        ([2], [1, 2, 10]),
+    ])
+    def test_padding(self, steps, result):
+        loc = mticker.MaxNLocator(steps=steps)
+        assert (loc._steps == result).all()
+
 
 class TestLinearLocator:
     def test_basic(self):
         loc = mticker.LinearLocator(numticks=3)
         test_value = np.array([-0.8, -0.3, 0.2])
         assert_almost_equal(loc.tick_values(-0.8, 0.2), test_value)
 
+    def test_zero_numticks(self):
+        loc = mticker.LinearLocator(numticks=0)
+        loc.tick_values(-0.8, 0.2) == []
+
     def test_set_params(self):
         """
         Create linear locator with presets={}, numticks=2 and change it to
@@ -55,6 +80,15 @@ def test_set_params(self):
         assert loc.numticks == 8
         assert loc.presets == {(0, 1): []}
 
+    def test_presets(self):
+        loc = mticker.LinearLocator(presets={(1, 2): [1, 1.25, 1.75],
+                                             (0, 2): [0.5, 1.5]})
+        assert loc.tick_values(1, 2) == [1, 1.25, 1.75]
+        assert loc.tick_values(2, 1) == [1, 1.25, 1.75]
+        assert loc.tick_values(0, 2) == [0.5, 1.5]
+        assert loc.tick_values(0.0, 2.0) == [0.5, 1.5]
+        assert (loc.tick_values(0, 1) == np.linspace(0, 1, 11)).all()
+
 
 class TestMultipleLocator:
     def test_basic(self):
@@ -590,6 +624,23 @@ def test_values(self, vmin, vmax, expected):
         ticks = sym.tick_values(vmin=vmin, vmax=vmax)
         assert_array_equal(ticks, expected)
 
+    def test_subs(self):
+        sym = mticker.SymmetricalLogLocator(base=10, linthresh=1, subs=[2.0, 4.0])
+        sym.create_dummy_axis()
+        sym.axis.set_view_interval(-10, 10)
+        assert (sym() == [-20., -40.,  -2.,  -4.,   0.,   2.,   4.,  20.,  40.]).all()
+
+    def test_extending(self):
+        sym = mticker.SymmetricalLogLocator(base=10, linthresh=1)
+        sym.create_dummy_axis()
+        sym.axis.set_view_interval(8, 9)
+        assert (sym() == [1.0]).all()
+        sym.axis.set_view_interval(8, 12)
+        assert (sym() == [1.0, 10.0]).all()
+        assert sym.view_limits(10, 10) == (1, 100)
+        assert sym.view_limits(-10, -10) == (-100, -1)
+        assert sym.view_limits(0, 0) == (-0.001, 0.001)
+
 
 class TestAsinhLocator:
     def test_init(self):
diff --git a/lib/matplotlib/ticker.py b/lib/matplotlib/ticker.py
@@ -657,12 +657,12 @@ def format_data(self, value):
         # docstring inherited
         e = math.floor(math.log10(abs(value)))
         s = round(value / 10**e, 10)
-        exponent = self._format_maybe_minus_and_locale("%d", e)
         significand = self._format_maybe_minus_and_locale(
             "%d" if s % 1 == 0 else "%1.10g", s)
         if e == 0:
             return significand
-        elif self._useMathText or self._usetex:
+        exponent = self._format_maybe_minus_and_locale("%d", e)
+        if self._useMathText or self._usetex:
             exponent = "10^{%s}" % exponent
             return (exponent if s == 1  # reformat 1x10^y as 10^y
                     else rf"{significand} \times {exponent}")
@@ -675,7 +675,6 @@ def get_offset(self):
         """
         if len(self.locs) == 0:
             return ''
-        s = ''
         if self.orderOfMagnitude or self.offset:
             offsetStr = ''
             sciNotStr = ''
@@ -694,8 +693,8 @@ def get_offset(self):
                 s = fr'${sciNotStr}\mathdefault{{{offsetStr}}}$'
             else:
                 s = ''.join((sciNotStr, offsetStr))
-
-        return self.fix_minus(s)
+            return self.fix_minus(s)
+        return ''
 
     def set_locs(self, locs):
         # docstring inherited
@@ -1055,9 +1054,6 @@ def _non_decade_format(self, sign_string, base, fx, usetex):
 
     def __call__(self, x, pos=None):
         # docstring inherited
-        usetex = mpl.rcParams['text.usetex']
-        min_exp = mpl.rcParams['axes.formatter.min_exponent']
-
         if x == 0:  # Symlog
             return r'$\mathdefault{0}$'
 
@@ -1070,23 +1066,25 @@ def __call__(self, x, pos=None):
         is_x_decade = _is_close_to_int(fx)
         exponent = round(fx) if is_x_decade else np.floor(fx)
         coeff = round(b ** (fx - exponent))
-        if is_x_decade:
-            fx = round(fx)
 
         if self.labelOnlyBase and not is_x_decade:
             return ''
         if self._sublabels is not None and coeff not in self._sublabels:
             return ''
 
+        if is_x_decade:
+            fx = round(fx)
+
         # use string formatting of the base if it is not an integer
         if b % 1 == 0.0:
             base = '%d' % b
         else:
             base = '%s' % b
 
-        if abs(fx) < min_exp:
+        if abs(fx) < mpl.rcParams['axes.formatter.min_exponent']:
             return r'$\mathdefault{%s%g}$' % (sign_string, x)
         elif not is_x_decade:
+            usetex = mpl.rcParams['text.usetex']
             return self._non_decade_format(sign_string, base, fx, usetex)
         else:
             return r'$\mathdefault{%s%s^{%d}}$' % (sign_string, base, fx)
@@ -1554,7 +1552,7 @@ def symbol(self):
         symbol = self._symbol
         if not symbol:
             symbol = ''
-        elif mpl.rcParams['text.usetex'] and not self._is_latex:
+        elif not self._is_latex and mpl.rcParams['text.usetex']:
             # Source: http://www.personal.ceu.hu/tex/specchar.htm
             # Backslash must be first for this to work correctly since
             # it keeps getting added in
@@ -1801,8 +1799,6 @@ def __call__(self):
 
     def tick_values(self, vmin, vmax):
         vmin, vmax = mtransforms.nonsingular(vmin, vmax, expander=0.05)
-        if vmax < vmin:
-            vmin, vmax = vmax, vmin
 
         if (vmin, vmax) in self.presets:
             return self.presets[(vmin, vmax)]
@@ -2356,13 +2352,13 @@ def tick_values(self, vmin, vmax):
         numdec = math.floor(log_vmax) - math.ceil(log_vmin)
 
         if isinstance(self._subs, str):
-            _first = 2.0 if self._subs == 'auto' else 1.0
             if numdec > 10 or b < 3:
                 if self._subs == 'auto':
                     return np.array([])  # no minor or major ticks
                 else:
                     subs = np.array([1.0])  # major ticks
             else:
+                _first = 2.0 if self._subs == 'auto' else 1.0
                 subs = np.arange(_first, b)
         else:
             subs = self._subs
@@ -2386,23 +2382,14 @@ def tick_values(self, vmin, vmax):
         decades = np.arange(math.floor(log_vmin) - stride,
                             math.ceil(log_vmax) + 2 * stride, stride)
 
-        if hasattr(self, '_transform'):
-            ticklocs = self._transform.inverted().transform(decades)
-            if have_subs:
-                if stride == 1:
-                    ticklocs = np.ravel(np.outer(subs, ticklocs))
-                else:
-                    # No ticklocs if we have >1 decade between major ticks.
-                    ticklocs = np.array([])
-        else:
-            if have_subs:
-                if stride == 1:
-                    ticklocs = np.concatenate(
-                        [subs * decade_start for decade_start in b ** decades])
-                else:
-                    ticklocs = np.array([])
+        if have_subs:
+            if stride == 1:
+                ticklocs = np.concatenate(
+                    [subs * decade_start for decade_start in b ** decades])
             else:
-                ticklocs = b ** decades
+                ticklocs = np.array([])
+        else:
+            ticklocs = b ** decades
 
         _log.debug('ticklocs %r', ticklocs)
         if (len(subs) > 1
@@ -2422,8 +2409,8 @@ def view_limits(self, vmin, vmax):
         vmin, vmax = self.nonsingular(vmin, vmax)
 
         if mpl.rcParams['axes.autolimit_mode'] == 'round_numbers':
-            vmin = _decade_less_equal(vmin, self._base)
-            vmax = _decade_greater_equal(vmax, self._base)
+            vmin = _decade_less_equal(vmin, b)
+            vmax = _decade_greater_equal(vmax, b)
 
         return vmin, vmax
 
@@ -2503,7 +2490,6 @@ def __call__(self):
         return self.tick_values(vmin, vmax)
 
     def tick_values(self, vmin, vmax):
-        base = self._base
         linthresh = self._linthresh
 
         if vmax < vmin:
@@ -2540,6 +2526,8 @@ def tick_values(self, vmin, vmax):
         # Check if linear range is present
         has_b = (has_a and vmax > -linthresh) or (has_c and vmin < linthresh)
 
+        base = self._base
+
         def get_log_range(lo, hi):
             lo = np.floor(np.log(lo) / np.log(base))
             hi = np.ceil(np.log(hi) / np.log(base))
@@ -2573,11 +2561,7 @@ def get_log_range(lo, hi):
         if has_c:
             decades.extend(base ** (np.arange(c_lo, c_hi, stride)))
 
-        # Add the subticks if requested
-        if self._subs is None:
-            subs = np.arange(2.0, base)
-        else:
-            subs = np.asarray(self._subs)
+        subs = np.asarray(self._subs)
 
         if len(subs) > 1 or subs[0] != 1.0:
             ticklocs = []
@@ -2604,8 +2588,7 @@ def view_limits(self, vmin, vmax):
                 vmin = _decade_less(vmin, b)
                 vmax = _decade_greater(vmax, b)
 
-        result = mtransforms.nonsingular(vmin, vmax)
-        return result
+        return mtransforms.nonsingular(vmin, vmax)
 
 
 class AsinhLocator(Locator):
@@ -2773,7 +2756,7 @@ def tick_values(self, vmin, vmax):
         # linscale: ... 1e-3 1e-2 1e-1 1/2 1-1e-1 1-1e-2 1-1e-3 ...
         # b-scale : ... -3   -2   -1   0   1      2      3      ...
         def ideal_ticks(x):
-            return 10 ** x if x < 0 else 1 - (10 ** (-x)) if x > 0 else 1 / 2
+            return 10 ** x if x < 0 else 1 - (10 ** (-x)) if x > 0 else 0.5
 
         vmin, vmax = self.nonsingular(vmin, vmax)
         binf = int(
