tests: Implement mock weechat module and add some color tests.

tests/color_test.py

@@ -0,0 +1,26 @@
+import webcolors
+from hypothesis import given
+from hypothesis.strategies import sampled_from
+
+from matrix.colors import (Formatted, color_html_to_weechat,
+                           color_weechat_to_html)
+
+html_prism = ("<font color=maroon>T</font><font color=red>e</font><font "
+              "color=olive>s</font><font color=yellow>t</font>")
+
+weechat_prism = (
+    u"\x1b[038;5;1mT\x1b[039m\x1b[038;5;9me\x1b[039m\x1b[038;5;3ms\x1b[039m\x1b[038;5;11mt\x1b[039m"
+)
+
+first_16_html_colors = list(webcolors.HTML4_HEX_TO_NAMES.values())
+
+
+def test_prism():
+    formatted = Formatted.from_html(html_prism)
+    assert formatted.to_weechat() == weechat_prism
+
+
+@given(sampled_from(first_16_html_colors))
+def test_color_conversion(color_name):
+    assert color_weechat_to_html(
+        color_html_to_weechat(color_name)) == color_name