robustify Ansi module a bit

lib/rscons/ansi.rb

@@ -3,6 +3,8 @@ module Rscons
   module Ansi
     class << self
 
+      RESET = "\e[0m"
+
       # Write a message to an IO with ANSI escape codes.
       #
       # @param io [IO]
@@ -17,27 +19,57 @@ module Rscons
           do_color = do_ansi?(io)
         end
         out = ""
+        if do_color
+          current_color = RESET
+          desired_color = RESET
+          message.each do |m|
+            if m.is_a?(String)
+              lines = m.split("\n", -1)
+              lines.each_with_index do |line, i|
+                if line != ""
+                  if current_color != desired_color
+                    out += desired_color
+                    current_color = desired_color
+                  end
+                  out += line
+                end
+                if i < lines.size - 1
+                  # A newline follows
+                  if current_color != RESET
+                    out += RESET
+                    current_color = RESET
+                  end
+                  out += "\n"
+                end
+              end
+            else
+              case m
+              when :red;            desired_color = "\e[0;31m"
+              when :green;          desired_color = "\e[0;32m"
+              when :yellow;         desired_color = "\e[0;33m"
+              when :blue;           desired_color = "\e[0;34m"
+              when :magenta;        desired_color = "\e[0;35m"
+              when :cyan;           desired_color = "\e[0;36m"
+              when :white;          desired_color = "\e[0;37m"
+              when :boldred;        desired_color = "\e[1;31m"
+              when :boldgreen;      desired_color = "\e[1;32m"
+              when :boldyellow;     desired_color = "\e[1;33m"
+              when :boldblue;       desired_color = "\e[1;34m"
+              when :boldmagenta;    desired_color = "\e[1;35m"
+              when :boldcyan;       desired_color = "\e[1;36m"
+              when :boldwhite;      desired_color = "\e[1;37m"
+              when :bold;           desired_color = "\e[1m"
+              when :reset;          desired_color = RESET
+              end
+            end
+          end
+          if current_color != RESET
+            out += RESET
+          end
+        else
           message.each do |m|
             if m.is_a?(String)
               out += m
-          elsif do_color
-            case m
-            when :red
-              out += "\e[0;31m"
-            when :green
-              out += "\e[0;32m"
-            when :yellow
-              out += "\e[0;33m"
-            when :blue
-              out += "\e[0;34m"
-            when :magenta
-              out += "\e[0;35m"
-            when :cyan
-              out += "\e[0;36m"
-            when :white
-              out += "\e[0;37m"
-            when :reset
-              out += "\e[0m"
             end
           end
         end

spec/rscons/ansi_spec.rb

@@ -1,12 +1,79 @@
 module Rscons
   describe Ansi do
-    describe ".do_ansi?" do
+    let(:io) {double}
 
+    describe ".write" do
+      context "when not doing color" do
+        before(:each) do
+          stub_const("RUBY_PLATFORM", "linux")
+          allow(io).to receive(:tty?).and_return(false)
+        end
+
+        it "skips color attributes and just writes the String arguments" do
+          expect(io).to receive(:write).with("line 1\nline 2\n")
+          Ansi.write(io, :bold, "line ", :red, "1\nline ", :boldblue, "2", "\n")
+        end
+      end
+
+      context "when doing color" do
+        before(:each) do
+          stub_const("RUBY_PLATFORM", "linux")
+          allow(io).to receive(:tty?).and_return(true)
+        end
+
+        it "writes the expected ANSI escape codes" do
+          expect(io).to receive(:write).with("\e[1mline \e[0;31m1\e[0m\n\e[0;31mline \e[1;34m2\e[0m\n")
+          Ansi.write(io, :bold, "line ", :red, "1\nline ", :boldblue, "2", "\n")
+        end
+
+        it "ends with a reset sequence" do
+          expect(io).to receive(:write).with("\e[1;33mbold yellow\e[0m")
+          Ansi.write(io, :boldyellow, "bold yellow")
+        end
+
+        it "does not write a color sequence when it would be overwritten" do
+          expect(io).to receive(:write).with("\e[1;36mBOLD CYAN\e[0m\n")
+          Ansi.write(io, :boldyellow, :boldcyan, "BOLD CYAN\n")
+        end
+
+        it "uses the correct escape sequences for all colors" do
+          expect(io).to receive(:write).with("\e[0;31mHI\e[0m")
+          Ansi.write(io, :red, "HI")
+          expect(io).to receive(:write).with("\e[0;32mHI\e[0m")
+          Ansi.write(io, :green, "HI")
+          expect(io).to receive(:write).with("\e[0;33mHI\e[0m")
+          Ansi.write(io, :yellow, "HI")
+          expect(io).to receive(:write).with("\e[0;34mHI\e[0m")
+          Ansi.write(io, :blue, "HI")
+          expect(io).to receive(:write).with("\e[0;35mHI\e[0m")
+          Ansi.write(io, :magenta, "HI")
+          expect(io).to receive(:write).with("\e[0;36mHI\e[0m")
+          Ansi.write(io, :cyan, "HI")
+          expect(io).to receive(:write).with("\e[0;37mHI\e[0m")
+          Ansi.write(io, :white, "HI")
+          expect(io).to receive(:write).with("\e[1;31mHI\e[0m")
+          Ansi.write(io, :boldred, "HI")
+          expect(io).to receive(:write).with("\e[1;32mHI\e[0m")
+          Ansi.write(io, :boldgreen, "HI")
+          expect(io).to receive(:write).with("\e[1;33mHI\e[0m")
+          Ansi.write(io, :boldyellow, "HI")
+          expect(io).to receive(:write).with("\e[1;34mHI\e[0m")
+          Ansi.write(io, :boldblue, "HI")
+          expect(io).to receive(:write).with("\e[1;35mHI\e[0m")
+          Ansi.write(io, :boldmagenta, "HI")
+          expect(io).to receive(:write).with("\e[1;36mHI\e[0m")
+          Ansi.write(io, :boldcyan, "HI")
+          expect(io).to receive(:write).with("\e[1;37mHI\e[0m")
+          Ansi.write(io, :boldwhite, "HI")
+        end
+      end
+    end
+
+    describe ".do_ansi?" do
       context "on Windows" do
         it "returns true when IO is a fifo on an xterm" do
           stub_const("RUBY_PLATFORM", "mingw")
           expect(ENV).to receive(:[]).with("TERM").and_return("xterm")
-          io = double
           expect(io).to receive(:stat).and_return(Struct.new(:ftype).new("fifo"))
           expect(Ansi.__send__(:do_ansi?, io)).to be_truthy
         end
@@ -14,7 +81,6 @@ module Rscons
         it "returns false when TERM is not set appropriately" do
           stub_const("RUBY_PLATFORM", "mingw")
           expect(ENV).to receive(:[]).with("TERM").and_return(nil)
-          io = double
           expect(Ansi.__send__(:do_ansi?, io)).to be_falsey
         end
       end
@@ -22,12 +88,11 @@ module Rscons
       context "on POSIX" do
         it "returns true when IO is a TTY" do
           stub_const("RUBY_PLATFORM", "linux")
-          io = double
           expect(io).to receive(:tty?).and_return(true)
           expect(Ansi.__send__(:do_ansi?, io)).to be_truthy
         end
       end
+    end
 
   end
 end
-end