add Application class; update CLI and Script for new architecture

spec/rscons/application_spec.rb

@@ -0,0 +1,71 @@
+module Rscons
+  describe Application do
+
+    describe ".determine_n_threads" do
+      context "when specified by environment variable" do
+        before(:each) do
+          expect(ENV).to receive(:[]).with("RSCONS_NTHREADS").and_return("3")
+        end
+        it "returns the user-specified number of threads to use" do
+          expect(Rscons.application.__send__(:determine_n_threads)).to eq(3)
+        end
+      end
+
+      context "when not specified by environment variable" do
+        before(:each) do
+          expect(ENV).to receive(:[]).with("RSCONS_NTHREADS").and_return(nil)
+        end
+
+        context "on Linux" do
+          before(:each) do
+            expect(RbConfig::CONFIG).to receive(:[]).with("host_os").and_return("linux")
+          end
+          it "returns the number of processors from /proc/cpuinfo" do
+            expect(File).to receive(:read).with("/proc/cpuinfo").and_return(<<EOF)
+processor : 0
+processor   : 1
+EOF
+            expect(Rscons.application.__send__(:determine_n_threads)).to eq(2)
+          end
+        end
+
+        context "on Windows" do
+          before(:each) do
+            expect(RbConfig::CONFIG).to receive(:[]).with("host_os").and_return("mingw")
+          end
+          it "returns the number of logical processors that wmic reports" do
+            expect(Rscons).to receive(:`).with("wmic cpu get NumberOfLogicalProcessors /value").and_return("NumberOfLogicalProcessors=7")
+            expect(Rscons.application.__send__(:determine_n_threads)).to eq(7)
+          end
+        end
+
+        context "on Darwin" do
+          before(:each) do
+            expect(RbConfig::CONFIG).to receive(:[]).with("host_os").and_return("darwin")
+          end
+          it "returns the number of threads that sysctl reports" do
+            expect(Rscons).to receive(:`).with("sysctl -n hw.ncpu").and_return("6")
+            expect(Rscons.application.__send__(:determine_n_threads)).to eq(6)
+          end
+        end
+
+        context "on an unknown platform" do
+          before(:each) do
+            expect(RbConfig::CONFIG).to receive(:[]).with("host_os").and_return("other")
+          end
+          it "returns 1" do
+            expect(Rscons.application.__send__(:determine_n_threads)).to eq(1)
+          end
+        end
+
+        context "when an error occurs" do
+          it "returns 1" do
+            expect(RbConfig::CONFIG).to receive(:[]).with("host_os").and_raise("foo")
+            expect(Rscons.application.__send__(:determine_n_threads)).to eq(1)
+          end
+        end
+      end
+    end
+
+  end
+end