1 files changed, 29 insertions, 0 deletions
diff --git a/spec/rubyspec/core/fixnum/minus_spec.rb b/spec/rubyspec/core/fixnum/minus_spec.rb
new file mode 100644
index 0000000000..de3af05179
--- /dev/null
+++ b/spec/rubyspec/core/fixnum/minus_spec.rb
@@ -0,0 +1,29 @@
+require File.expand_path('../../../spec_helper', __FILE__)
+
+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 "returns a Bignum only if the result is too large to be a Fixnum" do
+    (5 - 10).should be_an_instance_of Fixnum
+    (-1 - bignum_value).should be_an_instance_of Bignum
+
+    bignum_zero = bignum_value.coerce(0).first
+    (1 - bignum_zero).should be_an_instance_of Fixnum
+    (fixnum_min - 1).should be_an_instance_of(Bignum)
+  end
+
+  it "raises a TypeError when given a non-Integer" do
+    lambda {
+      (obj = mock('10')).should_receive(:to_int).any_number_of_times.and_return(10)
+      13 - obj
+    }.should raise_error(TypeError)
+    lambda { 13 - "10"    }.should raise_error(TypeError)
+    lambda { 13 - :symbol }.should raise_error(TypeError)
+  end
+end