add core/fixnum/to_s spec

test/test-android/app/core/fixnum/to_s_spec.rb

@@ -0,0 +1,25 @@
+describe "Fixnum#to_s when given a base" do
+  it "returns self converted to a String in the given base" do
+    12345.to_s(2).should == "11000000111001"
+    12345.to_s(8).should == "30071"
+    12345.to_s(10).should == "12345"
+    12345.to_s(16).should == "3039"
+    12345.to_s(36).should == "9ix"
+  end
+
+  it "raises an ArgumentError if the base is less than 2 or higher than 36" do
+    lambda { 123.to_s(-1) }.should raise_error(ArgumentError)
+    lambda { 123.to_s(0)  }.should raise_error(ArgumentError)
+    lambda { 123.to_s(1)  }.should raise_error(ArgumentError)
+    lambda { 123.to_s(37) }.should raise_error(ArgumentError)
+  end
+end
+
+describe "Fixnum#to_s when no base given" do
+  it "returns self converted to a String using base 10" do
+    255.to_s.should == '255'
+    3.to_s.should == '3'
+    0.to_s.should == '0'
+    -9002.to_s.should == '-9002'
+  end
+end