Actually verify that non-string to_s is discarded

headius · headius · commit 74a1904ff8b1 · 2025-08-05T12:54:35.000+03:00
The old spec only verified that a dynamic string would be
successfully created when an interpolated object returned a
non-string value from to_s. This enhances the spec to also verify
that the non-string value will be discarded in favor of the generic
"hashy" inspect string.
diff --git a/spec/ruby/language/string_spec.rb b/spec/ruby/language/string_spec.rb
@@ -134,16 +134,14 @@ class << obj
   end
 
   it "uses an internal representation when #to_s doesn't return a String" do
-    obj = mock('to_s')
-    obj.stub!(:to_s).and_return(42)
-
-    # See rubyspec commit 787c132d by yugui. There is value in
-    # ensuring that this behavior works. So rather than removing
-    # this spec completely, the only thing that can be asserted
-    # is that if you interpolate an object that fails to return
-    # a String, you will still get a String and not raise an
-    # exception.
-    "#{obj}".should be_an_instance_of(String)
+    # don't use mocking so we have a predictable string representation below (#<Object...>)
+    obj = Object.new
+    def obj.to_s
+      42
+    end
+
+    # ensure the interpolation succeeds and the content included does not include the non-string value.
+    "#{obj}".should =~ /#<Object:0x[0-9a-fA-F]+>/
   end
 
   it "allows a dynamic string to parse a nested do...end block as an argument to a call without parens, interpolated" do
