FIX: changed to AttributeError

Author: jklymak

lib/matplotlib/axis.py

@@ -1568,9 +1568,9 @@ def set_major_formatter(self, formatter):
 
         ACCEPTS: A :class:`~matplotlib.ticker.Formatter` instance
         """
-        if not isinstance(formatter, mticker.Formatter):
-            raise ValueError(
-                    "formatter argument must be matplotlib.ticker.Formatter")
+        if not hasattr(formatter, 'format_data'):
+            raise AttributeError("formatter argument should be instance of "
+                    "matplotlib.ticker.Formatter")
         self.isDefault_majfmt = False
         self.major.formatter = formatter
         formatter.set_axis(self)
@@ -1582,9 +1582,9 @@ def set_minor_formatter(self, formatter):
 
         ACCEPTS: A :class:`~matplotlib.ticker.Formatter` instance
         """
-        if not isinstance(formatter, mticker.Formatter):
-            raise ValueError(
-                    "formatter argument must be matplotlib.ticker.Formatter")
+        if not hasattr(formatter, 'format_data'):
+            raise AttributeError("formatter argument should be instance of "
+                    "matplotlib.ticker.Formatter")
         self.isDefault_minfmt = False
         self.minor.formatter = formatter
         formatter.set_axis(self)
@@ -1596,9 +1596,9 @@ def set_major_locator(self, locator):
 
         ACCEPTS: a :class:`~matplotlib.ticker.Locator` instance
         """
-        if not isinstance(locator, mticker.Locator):
-            raise ValueError(
-                    "locator argument must be matplotlib.ticker.Locator")
+        if not hasattr(locator, 'tick_values'):
+            raise AttributeError("formatter argument should be instance of "
+                    "matplotlib.ticker.Locator")
         self.isDefault_majloc = False
         self.major.locator = locator
         locator.set_axis(self)
@@ -1610,9 +1610,9 @@ def set_minor_locator(self, locator):
 
         ACCEPTS: a :class:`~matplotlib.ticker.Locator` instance
         """
-        if not isinstance(locator, mticker.Locator):
-            raise ValueError(
-                    "locator argument must be matplotlib.ticker.Locator")
+        if not hasattr(locator, 'tick_values'):
+            raise AttributeError("formatter argument should be instance of "
+                    "matplotlib.ticker.Locator")
         self.isDefault_minloc = False
         self.minor.locator = locator
         locator.set_axis(self)

lib/matplotlib/tests/test_ticker.py

@@ -732,23 +732,23 @@ def test_latex(self, is_latex, usetex, expected):
 
 def test_majformatter_type():
     fig, ax = plt.subplots()
-    with pytest.raises(ValueError):
+    with pytest.raises(AttributeError):
         ax.xaxis.set_major_formatter(matplotlib.ticker.LogLocator())
 
 
 def test_minformatter_type():
     fig, ax = plt.subplots()
-    with pytest.raises(ValueError):
+    with pytest.raises(AttributeError):
         ax.xaxis.set_minor_formatter(matplotlib.ticker.LogLocator())
 
 
 def test_majlocator_type():
     fig, ax = plt.subplots()
-    with pytest.raises(ValueError):
+    with pytest.raises(AttributeError):
         ax.xaxis.set_major_locator(matplotlib.ticker.LogFormatter())
 
 
 def test_minlocator_type():
     fig, ax = plt.subplots()
-    with pytest.raises(ValueError):
+    with pytest.raises(AttributeError):
         ax.xaxis.set_minor_locator(matplotlib.ticker.LogFormatter())