Give a nicer error message in tests when the location could not be found

src/Review/Test.elm

@@ -879,11 +879,8 @@ checkMessageAppearsUnder codeInspector error_ (ExpectedError expectedError) =
                         ]
 
         Nothing ->
-            -- TODO Fail with a more precise error message
+            ErrorMessage.locationNotFound error_
-            -- This is actually quite easy to create. We can enter this here by
+                |> Expect.fail
-            -- having the location be
-            -- { start = { row = 0, column = 0 }, end = { row = 0, column = 0 } }
-            Expect.fail ErrorMessage.impossibleState
                 |> always
 
 

src/Review/Test/ErrorMessage.elm

@@ -1,10 +1,9 @@
 module Review.Test.ErrorMessage exposing
     ( ExpectedErrorData
     , parsingFailure, messageMismatch, emptyDetails, unexpectedDetails, wrongLocation, didNotExpectErrors
-    , underMismatch, expectedMoreErrors, tooManyErrors, locationIsAmbiguousInSourceCode
+    , underMismatch, expectedMoreErrors, tooManyErrors, locationNotFound, locationIsAmbiguousInSourceCode
     , needToUsedExpectErrorsForModules, duplicateModuleName, unknownModulesInExpectedErrors
     , missingFixes, unexpectedFixes, fixedCodeMismatch, unchangedSourceAfterFix, invalidSourceAfterFix, hasCollisionsInFixRanges
-    , impossibleState
     )
 
 {-| Error messages for the `Review.Test` module.
@@ -14,10 +13,9 @@ module Review.Test.ErrorMessage exposing
 
 @docs ExpectedErrorData
 @docs parsingFailure, messageMismatch, emptyDetails, unexpectedDetails, wrongLocation, didNotExpectErrors
-@docs underMismatch, expectedMoreErrors, tooManyErrors, locationIsAmbiguousInSourceCode
+@docs underMismatch, expectedMoreErrors, tooManyErrors, locationNotFound, locationIsAmbiguousInSourceCode
 @docs needToUsedExpectErrorsForModules, duplicateModuleName, unknownModulesInExpectedErrors
 @docs missingFixes, unexpectedFixes, fixedCodeMismatch, unchangedSourceAfterFix, invalidSourceAfterFix, hasCollisionsInFixRanges
-@docs impossibleState
 
 -}
 
@@ -218,6 +216,22 @@ I found """
         ++ listErrorMessagesAndPositions extraErrors
 
 
+locationNotFound : Error -> String
+locationNotFound error =
+    """COULD NOT FIND LOCATION FOR ERROR
+
+I was looking for the error with the following message:
+
+  """ ++ wrapInQuotes (Rule.errorMessage error) ++ """
+
+and I found it, but the code it points to does not lead to anything:
+
+  """ ++ rangeAsString (Rule.errorRange error) ++ """
+
+Please try to have the error under the smallest region that makes sense.
+This will be the most helpful for the person who reads the error message."""
+
+
 locationIsAmbiguousInSourceCode : SourceCode -> Error -> String -> List Int -> String
 locationIsAmbiguousInSourceCode sourceCode error under occurrencesInSourceCode =
     """AMBIGUOUS ERROR LOCATION
@@ -289,13 +303,6 @@ match the names of the modules in the test source codes to the ones in the
 expected errors list."""
 
 
-impossibleState : String
-impossibleState =
-    """ELM-REVIEW IMPOSSIBLE STATE
-
-Oh no! I'm in an impossible state! I found an error at a location that I could not trace back. Please let me know and give me an SSCCE (http://sscce.org/) here: https://github.com/jfmengels/elm-review/issues."""
-
-
 missingFixes : ExpectedErrorData -> String
 missingFixes expectedError =
     """MISSING FIXES

tests/ErrorMessageTest.elm

@@ -18,6 +18,7 @@ all =
         , unexpectedDetailsTest
         , emptyDetailsTest
         , wrongLocationTest
+        , locationNotFoundTest
         , expectedMoreErrorsTest
         , tooManyErrorsTest
         , locationIsAmbiguousInSourceCodeTest
@@ -427,6 +428,36 @@ but I found it at:
         ]
 
 
+locationNotFoundTest : Test
+locationNotFoundTest =
+    test "locationNotFound" <|
+        \() ->
+            let
+                error : Error
+                error =
+                    Rule.error
+                        { message = "Some error"
+                        , details = [ "Some details" ]
+                        }
+                        { start = { row = 0, column = 0 }, end = { row = 0, column = 0 } }
+            in
+            ErrorMessage.locationNotFound error
+                |> expectMessageEqual """
+COULD NOT FIND LOCATION FOR ERROR
+
+I was looking for the error with the following message:
+
+  `Some error`
+
+and I found it, but the code it points to does not lead to anything:
+
+  { start = { row = 0, column = 0 }, end = { row = 0, column = 0 } }
+
+Please try to have the error under the smallest region that makes sense.
+This will be the most helpful for the person who reads the error message.
+"""
+
+
 expectedMoreErrorsTest : Test
 expectedMoreErrorsTest =
     test "expectedMoreErrors" <|