Add a couple of tests for the dark theme

test/density_dark.jl

@@ -0,0 +1,27 @@
+using Base.Test
+using Gadfly, DataArrays, RDatasets, Distributions
+
+global density_dark_tested
+
+p = Gadfly.with_theme(:dark) do
+    plot(dataset("ggplot2", "diamonds"), x="Price", color="Cut", Geom.density)
+end
+
+# prevent these tests from running more than once
+if !isdefined(:density_dark_tested)
+    svg_str_dark = stringmime(MIME("image/svg+xml"), p)
+    @test contains(svg_str_dark, hex(Gadfly.dark_theme.default_color))
+    @test contains(svg_str_dark, hex(Gadfly.dark_theme.background_color))
+    @test contains(svg_str_dark, hex(Gadfly.dark_theme.panel_fill))
+
+    # Test reset.
+    p2 = plot(dataset("ggplot2", "diamonds"), x="Price", color="Cut", Geom.density)
+    svg_str_light = stringmime(MIME("image/svg+xml"), p2)
+    @test !contains(svg_str_light, hex(Gadfly.dark_theme.default_color))
+    @test !contains(svg_str_light, hex(Gadfly.dark_theme.background_color))
+    @test !contains(svg_str_light, hex(Gadfly.dark_theme.panel_fill))
+
+    density_dark_tested=true
+end
+
+p

test/hexbin_dark.jl

@@ -0,0 +1,8 @@
+
+using Gadfly, Distributions
+
+vals = rand(MultivariateNormal([0.0, 0.0], [1.0 0.5; 0.5 1.0]), 10000)
+Gadfly.with_theme(:dark) do
+    plot(x=vals[1,:], y=vals[2,:], Geom.hexbin)
+end
+

test/runtests.jl

@@ -42,6 +42,7 @@ tests = [
     ("histogram2d",                           6inch, 3inch),
     ("rectbin",                               6inch, 3inch),
     ("density",                               6inch, 3inch),
+    ("density_dark",                          6inch, 3inch),
     ("colorful_density",                      6inch, 3inch),
     ("explicit_colorkey_title",               6inch, 3inch),
     ("explicit_subplot_titles",               6inch, 3inch),
@@ -70,6 +71,7 @@ tests = [
     ("ordered_line",                          6inch, 3inch),
     ("nan_skipping",                          6inch, 3inch),
     ("hexbin",                                6inch, 3inch),
+    ("hexbin_dark",                           6inch, 3inch),
     ("spy",                                   6inch, 3inch),
     ("issue177",                              6inch, 3inch),
     ("ribbon",                                6inch, 3inch),