Improve message from refute on failure

The previous implementation was to `assert(!value)` which led to
confusing failure messages when using `refute` directly.

For custom failure messages, `!value` is always `false` on failure, so
`false` is passed to the custom message block where the caller might
instead expect the value that caused the failure.

Similarly, the default failure message is always "expected false to be
truthy" when really the expectation is that something truthy is falsy.

Author: z1lk

lib/quickdraw/test.rb

@@ -49,8 +49,16 @@ def assert(value)
 		nil
 	end
 
-	def refute(value, ...)
-		assert(!value, ...)
+	def refute(value)
+		if !value
+			success!
+		elsif block_given?
+			failure! { yield(value) }
+		else
+			failure! { "expected #{value.inspect} to be falsy" }
+		end
+
+		nil
 	end
 
 	# Indicate that an assertion passed successfully.

test/quickdraw.test.rb

@@ -15,3 +15,17 @@
 test "refute", skip: true do
 	refute true
 end
+
+test "refute custom message" do
+	runner = assert_test(failures: 1) do
+		refute(32) { |val| "#{val} not falsy" }
+	end
+	assert_equal runner.failures.last["message"], "32 not falsy"
+end
+
+test "refute default message" do
+	runner = assert_test(failures: 1) do
+		refute 32
+	end
+	assert_equal runner.failures.last["message"], "expected 32 to be falsy"
+end