added preliminary handling for errors

lib/rspec-extensions/expectations.rb

@@ -1,7 +1,16 @@
 module RspecExtensions
   module Expectations
-    def expect value
-      yield.should == value
+    def expect *args, &block
+      value = args.shift
+      if Class === value
+        if args.empty?
+          block.should raise_error(value)
+        else
+          block.should raise_error(value, args.first)
+        end
+      else
+        block.call.should == value
+      end
     end
   end
 end

spec/rspec-extensions/expectations_spec.rb

@@ -1,18 +1,64 @@
 require File.join(File.dirname(__FILE__), %w[.. helper])
 
-describe "expect value" do
+describe RspecExtensions::Expectations do
   include RspecExtensions::Expectations
-  it "should work just like should ==" do
-    expect 3 do
-      1 + 2
+
+  describe "expect value" do
+    it "should work just like should ==" do
+      expect 3 do
+        1 + 2
+      end
     end
-  end
 
-  it "should fail just like should ==" do
-    lambda {
-      expect 3 do
-        1 + 1
+    it "should fail just like should ==" do
+      lambda do
+        expect 3 do
+          1 + 1
+        end
+      end.should raise_error(/expected: 3.*got: 2/m)
+    end
+  end
+
+  describe "expect error" do
+    describe "when the block raises the expected error" do
+      it "should pass with Exception" do
+        expect Exception do
+          raise "this error"
+        end
       end
-    }.should raise_error(/expected: 3.*got: 2/m)
+      it "should pass with a subclass of the named exception" do
+        expect NameError do
+          raise 1.non_existent_method
+        end
+      end
+    end
+
+    describe "when the block raises the expected error and message" do
+      it "should pass" do
+        expect NameError, /undefined/ do
+          raise 1.non_existent_method
+        end
+      end
+    end
+
+    describe "when the block raises the expected error with the wrong message" do
+      it "should fail" do
+        lambda do
+          expect NameError, /wrong message/ do
+            raise 1.non_existent_method
+          end
+        end.should raise_error(/expected NameError/)
+      end
+    end
+
+    describe "when the block raises the wrong error" do
+      it "should fail" do
+        lambda do
+          expect NameError do
+            raise "this is not a name error"
+          end
+        end.should raise_error(/expected/)
+      end
+    end
   end
-end
+end