Organize legend regression tests.

Author: tshead2

features/legends.feature

@@ -2,16 +2,16 @@ Feature: Legends
   Scenario Outline: Render legends
     Given a default canvas
     And a set of cartesian axes
-    And <data>
-    And the data is rendered as <mark>
-    And the marks are added to a legend
-    And the legend is added to the <target>
+    And <scenario>
+    And the marks are used to create a legend
     Then the figure should match the <reference> reference image
 
     Examples:
-      | data                                    | mark       | target    | reference                       |
-      | single and multi series data            | bars       | canvas    | legend-canvas-bar               |
-      | single and multi series data            | fills       | canvas    | legend-canvas-fill               |
-      | single and multi series data            | plots       | canvas    | legend-canvas-plot               |
-      | single and multi series data            | scatterplots       | canvas    | legend-canvas-scatterplot               |
+      | scenario                                | reference                       |
+      | the data is rendered as boundary bars   | legend-boundary-bars               |
+      | the data is rendered as magnitude bars  | legend-magnitude-bars               |
+      | the data is rendered as boundary fills  | legend-boundary-fills               |
+      | the data is rendered as magnitude fills  | legend-magnitude-fills               |
+      | the data is rendered as plots           | legend-plots               |
+      | the data is rendered as scatterplots    | legend-scatterplots               |