Merge remote-tracking branch 'origin/bugfix-3' into bugfix-1

2 files changed, 27 insertions, 24 deletions

diff --git a/blessings/__init__.py b/blessings/__init__.py
index bee547e..f7c1659 100644
--- a/blessings/__init__.py
+++ b/blessings/__init__.py
@@ -302,7 +302,8 @@ class Terminal(object):
         :arg num: The number, 0-15, of the color
 
         """
-        return ParametrizingString(self._foreground_color, self.normal)
+        return (ParametrizingString(self._foreground_color, self.normal)
+                if self.does_styling else NullCallableString())
 
     @property
     def on_color(self):
@@ -311,7 +312,8 @@ class Terminal(object):
         See ``color()``.
 
         """
-        return ParametrizingString(self._background_color, self.normal)
+        return (ParametrizingString(self._background_color, self.normal)
+                if self.does_styling else NullCallableString())
 
     @property
     def number_of_colors(self):
@@ -333,11 +335,11 @@ class Terminal(object):
         # don't name it after the underlying capability, because we deviate
         # slightly from its behavior, and we might someday wish to give direct
         # access to it.
-        colors = tigetnum('colors')  # Returns -1 if no color support, -2 if no
-                                     # such cap.
+        # Returns -1 if no color support, -2 if no such capability.
+        colors = self.does_styling and tigetnum('colors') or -1
         #  self.__dict__['colors'] = ret  # Cache it. It's not changing.
                                           # (Doesn't work.)
-        return colors if colors >= 0 else 0
+        return max(0, colors)
 
     def _resolve_formatter(self, attr):
         """Resolve a sugary or plain capability name, color, or compound
@@ -391,6 +393,8 @@ class Terminal(object):
         # bright colors at 8-15:
         offset = 8 if 'bright_' in color else 0
         base_color = color.rsplit('_', 1)[-1]
+        if self.number_of_colors == 0:
+            return NullCallableString()
         return self._formatting_string(
             color_cap(getattr(curses, 'COLOR_' + base_color.upper()) + offset))
 
@@ -447,12 +451,6 @@ class ParametrizingString(unicode):
             parametrized = tparm(self.encode('utf-8'), *args).decode('utf-8')
             return (parametrized if self._normal is None else
                     FormattingString(parametrized, self._normal))
-        except curses.error:
-            # Catch "must call (at least) setupterm() first" errors, as when
-            # running simply `nosetests` (without progressive) on nose-
-            # progressive. Perhaps the terminal has gone away between calling
-            # tigetstr and calling tparm.
-            return u''
         except TypeError:
             # If the first non-int (i.e. incorrect) arg was a string, suggest
             # something intelligent:
@@ -526,7 +524,12 @@ class NullCallableString(unicode):
             # determine which of 2 special-purpose classes,
             # NullParametrizableString or NullFormattingString, to return, and
             # retire this one.
-            return u''
+            # As a NullCallableString, even when provided with a parameter,
+            # such as t.color(5), we must also still be callable, fe:
+            # >>> t.color(5)('shmoo')
+            # is actually simplified result of NullCallable()(), so
+            # turtles all the way down: we return another instance.
+            return NullCallableString()
         return args[0]  # Should we force even strs in Python 2.x to be
                         # unicodes? No. How would I know what encoding to use
                         # to convert it?
diff --git a/blessings/tests.py b/blessings/tests.py
index 168c396..ee9c3c8 100644
--- a/blessings/tests.py
+++ b/blessings/tests.py
@@ -137,23 +137,23 @@ def test_null_fileno():
 
 def test_mnemonic_colors():
     """Make sure color shortcuts work."""
-    def color(num):
-        return unicode_parm('setaf', num)
+    def color(t, num):
+        return t.number_of_colors and unicode_parm('setaf', num) or ''
 
-    def on_color(num):
-        return unicode_parm('setab', num)
+    def on_color(t, num):
+        return t.number_of_colors and unicode_parm('setab', num) or ''
 
     # Avoid testing red, blue, yellow, and cyan, since they might someday
     # change depending on terminal type.
     t = TestTerminal()
-    eq_(t.white, color(7))
-    eq_(t.green, color(2))  # Make sure it's different than white.
-    eq_(t.on_black, on_color(0))
-    eq_(t.on_green, on_color(2))
-    eq_(t.bright_black, color(8))
-    eq_(t.bright_green, color(10))
-    eq_(t.on_bright_black, on_color(8))
-    eq_(t.on_bright_green, on_color(10))
+    eq_(t.white, color(t, 7))
+    eq_(t.green, color(t, 2))  # Make sure it's different than white.
+    eq_(t.on_black, on_color(t, 0))
+    eq_(t.on_green, on_color(t, 2))
+    eq_(t.bright_black, color(t, 8))
+    eq_(t.bright_green, color(t, 10))
+    eq_(t.on_bright_black, on_color(t, 8))
+    eq_(t.on_bright_green, on_color(t, 10))
 
 
 def test_callable_numeric_colors():