protect against diff guard condition failing

grosser · Nov 5, 2023 · 52491ec · 52491ec
1 parent 21507bc
commit 52491ec
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diff --git a/lib/kennel/models/record.rb b/lib/kennel/models/record.rb
@@ -96,7 +96,9 @@ def diff(actual)
         # strict: ignore Integer vs Float
         # similarity: show diff when not 100% similar
         # use_lcs: saner output
-        Hashdiff.diff(actual, expected, use_lcs: false, strict: false, similarity: 1)
+        result = Hashdiff.diff(actual, expected, use_lcs: false, strict: false, similarity: 1)
+        raise "Empty diff detected: guard condition failed" if result.empty?
+        result
       end
 
       def tracking_id

diff --git a/test/kennel/models/record_test.rb b/test/kennel/models/record_test.rb
@@ -226,6 +226,13 @@ def diff_resource(e, a)
     it "ignores numeric class difference since the api is semi random on these" do
       diff_resource({ a: 1 }, a: 1.0).must_equal []
     end
+
+    it "alerts when guard condition is ineffective" do
+      # if something is "diff equal" but not "==" then we are leaving speed on the table
+      Hashdiff.expects(:diff).returns []
+      e = assert_raises(RuntimeError) { diff_resource({ a: 1 }, a: 2) }
+      e.message.must_include "Empty diff detected"
+    end
   end
 
   describe "#tracking_id" do