add core/fixnum/minus spec

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

@@ -0,0 +1,24 @@
+class Core_Fixnum_Minus_Mock1 < Java::Lang::Object
+  def to_int
+    10
+  end
+end
+
+describe "Fixnum#-" do
+  it "returns self minus the given Integer" do
+    (5 - 10).should == -5
+    (9237212 - 5_280).should == 9231932
+
+    (781 - 0.5).should == 780.5
+    (2_560_496 - bignum_value).should == -9223372036852215312
+  end
+
+  it "raises a TypeError when given a non-Integer" do
+    lambda {
+      obj = Core_Fixnum_Minus_Mock1.new
+      13 - obj
+    }.should raise_error(TypeError)
+    lambda { 13 - "10"    }.should raise_error(TypeError)
+    lambda { 13 - :symbol }.should raise_error(TypeError)
+  end
+end