Issue rspec#133: Disallow at_least(0).

lib/rspec/mocks/error_generator.rb

@@ -66,6 +66,11 @@ def raise_wrong_arity_error(args_to_yield, arity)
         __raise "#{intro} yielded |#{arg_list(*args_to_yield)}| to block with arity of #{arity}"
       end
 
+      # @private
+      def raise_wrong_expected_receive_count_error(message)
+        __raise "#{intro} received :#{message} with invalid expectation\n     expected: at_least(n) with n > 0 \n     got: 0"
+      end
+
       private
 
       def intro

lib/rspec/mocks/message_expectation.rb

@@ -233,6 +233,11 @@ def matches_at_least_count?
         @at_least && @actual_received_count >= @expected_received_count
       end
 
+      # @private
+      def at_least_count_greater_than_zero?(n)
+        @at_least ?  n > 0 : true
+      end
+
       # @private
       def matches_at_most_count?
         @at_most && @actual_received_count <= @expected_received_count
@@ -266,6 +271,10 @@ def raise_out_of_order_error
         @error_generator.raise_out_of_order_error @message
       end
 
+      def raise_wrong_expected_receive_count_error
+        @error_generator.raise_wrong_expected_receive_count_error(@message)
+      end
+
       # Constrains a stub or message expectation to invocations with specific
       # arguments.
       #
@@ -449,8 +458,15 @@ def set_expected_received_count(relativity, n)
         @at_least = (relativity == :at_least)
         @at_most  = (relativity == :at_most)
         @exactly  = (relativity == :exactly)
+
         @expected_received_count = case n
-                                   when Numeric then n
+                                   when Numeric
+                                    if at_least_count_greater_than_zero?(n) 
+                                      n
+                                    else
+                                      @expected_received_count = 0
+                                      raise_wrong_expected_receive_count_error
+                                    end
                                    when :once   then 1
                                    when :twice  then 2
                                    end
@@ -466,6 +482,7 @@ def build_implementation(values)
         value = values.size == 1 ? values.first : values
         lambda { value }
       end
+
     end
 
     # @private

spec/rspec/mocks/at_least_spec.rb

@@ -97,33 +97,11 @@ module Mocks
         @double.rspec_verify
       end
 
-      it "passes with at_least(0) with no return if called once" do
-        @double.should_receive(:do_something).at_least(0).times
-        @double.do_something
-      end
 
-      it "passes with at_least(0) with return block if called once" do
-        @double.should_receive(:do_something).at_least(0).times { true }
-        @double.do_something
+      it "raises wrong expected receive count error when the at least 0 method is called" do
+        expect{ @double.should_receive(:do_something).at_least(0) }.to raise_error(RSpec::Mocks::MockExpectationError, /expected: at_least\(n\) with n > 0/)
       end
-
-      it "passes with at_least(0) with and_return if called once" do
-        @double.should_receive(:do_something).at_least(0).times.and_return true
-        @double.do_something
-      end
-
-      it "passes with at_least(0) with no return if never called" do
-        @double.should_receive(:do_something).at_least(0).times
-      end
-
-      it "passes with at_least(0) with return block if never called" do
-        @double.should_receive(:do_something).at_least(0).times { true }
-      end
-
-      it "passes with at_least(0) with and_return if never called" do
-        @double.should_receive(:do_something).at_least(0).times.and_return true
-      end
-
+
       it "uses a stub value if no value set" do
         @double.stub(:do_something => 'foo')
         @double.should_receive(:do_something).at_least(:once)