Improve doctest expectation messages

Author: José Valim

lib/ex_unit/lib/ex_unit/assertions.ex

@@ -1,11 +1,18 @@
 defexception ExUnit.AssertionError,  message: "assertion failed"
 
-defexception ExUnit.ExpectationError, expected: nil, actual: nil, reason: "", negation: false, prelude: "Expected", instead: nil, instead_prelude: "instead got" do
+defexception ExUnit.ExpectationError, expected: nil, actual: nil, reason: "", negation: false, prelude: "Expected", description: nil do
   def message(exception) do
-    "#{exception.prelude} #{exception.expected} to " <>
-      if(exception.negation, do: "not ", else: "") <>
-      "#{exception.reason} #{exception.actual}" <>
-      if(exception.instead, do: ". #{exception.instead_prelude} #{exception.instead}", else: "")
+    if desc = exception.description do
+      "#{exception.prelude} #{desc} #{exception.full_reason} " <>
+        "#{exception.expected}. Insted got #{exception.actual}"
+    else
+      "#{exception.prelude} #{exception.expected} " <>
+        "#{exception.full_reason} #{exception.actual}"
+    end
+  end
+
+  def full_reason(exception) do
+    "to" <> if(exception.negation, do: " not ", else: " ") <> exception.reason
   end
 end
 

lib/ex_unit/lib/ex_unit/cli_formatter.ex

@@ -89,18 +89,20 @@ defmodule ExUnit.CLIFormatter do
     acc + 1
   end
 
-  defp print_kind_reason(:error, record) when is_record(record, ExUnit.ExpectationError) do
-    left  = String.downcase record.prelude
-    right = "to " <> if(record.negation, do: "not ", else: "") <> record.reason
-    instead_prelude = record.instead_prelude
-    max   = max(size(left), size(right))
+  defp print_kind_reason(:error, ExUnit.ExpectationError[] = record) do
+    prelude  = String.downcase record.prelude
+    reason   = record.full_reason
+    max      = max(size(prelude), size(reason))
 
     IO.puts error_info "** (ExUnit.ExpectationError)"
-    IO.puts error_info "  #{pad(left, max)}: #{maybe_multiline(record.expected, max)}"
-    IO.puts error_info "  #{pad(right, max)}: #{maybe_multiline(record.actual, max)}"
 
-    unless nil?(record.instead) do
-      IO.puts error_info "  #{pad(instead_prelude, max)}: #{maybe_multiline(inspect(record.instead), max)}"
+    if desc = record.description do
+      IO.puts error_info "  #{pad(prelude, max)}: #{maybe_multiline(desc, max)}"
+      IO.puts error_info "  #{pad(reason, max)}: #{maybe_multiline(record.expected, max)}"
+      IO.puts error_info "  #{pad("instead got", max)}: #{maybe_multiline(record.actual, max)}"
+    else
+      IO.puts error_info "  #{pad(prelude, max)}: #{maybe_multiline(record.expected, max)}"
+      IO.puts error_info "  #{pad(reason, max)}: #{maybe_multiline(record.actual, max)}"
     end
   end
 

lib/ex_unit/lib/ex_unit/doc_test.ex

@@ -167,25 +167,25 @@ defmodule ExUnit.DocTest do
         v = unquote(expected_ast)
         case unquote(expr_ast) do
           ^v -> :ok
-          instead ->
+          actual ->
             raise ExUnit.ExpectationError,
               [ prelude: "Expected doctest",
-                expected: unquote(test.expr),
-                actual: inspect(v),
+                description: unquote(test.expr),
+                expected: inspect(v),
                 reason: "evaluate to",
-                instead: instead ],
+                actual: inspect(actual) ],
               unquote(stack)
         end
       rescue
         e in [ExUnit.ExpectationError] ->
           raise e, [], unquote(stack)
-        e ->
+        actual ->
           raise ExUnit.ExpectationError,
             [ prelude: "Expected doctest",
-              expected: unquote(test.expr),
-              actual: "without an exception",
+              description: unquote(test.expr),
+              expected: "without an exception",
               reason: "complete",
-              instead: e ],
+              actual: inspect(actual) ],
             unquote(stack)
       end
     end
@@ -206,30 +206,30 @@ defmodule ExUnit.DocTest do
         v = unquote(expr_ast)
         raise ExUnit.ExpectationError,
           [ prelude: "Expected doctest",
-            expected: unquote(test.expr),
-            actual: "by raising #{inspect unquote(exception)} exception",
-            reason: "terminate",
-            instead: v ],
+            description: unquote(test.expr),
+            expected: "#{inspect unquote(exception)}[]",
+            reason: "raise",
+            actual: inspect(v) ],
           unquote(stack)
       rescue
         e in [ExUnit.ExpectationError] -> raise(e)
         error in [unquote(exception)] ->
           unless error.message == unquote(message) do
             raise ExUnit.ExpectationError,
               [ prelude: "Expected doctest",
-                expected: unquote(test.expr),
-                actual: "by raising #{inspect unquote(exception)} exception with a #{inspect unquote(message)} message",
-                reason: "terminate",
-                instead: error ],
+                description: unquote(test.expr),
+                expected: "#{inspect unquote(exception)} with message #{inspect unquote(message)}",
+                reason: "raise",
+                actual: inspect(error) ],
               unquote(stack)
           end
         error ->
           raise ExUnit.ExpectationError,
             [ prelude: "Expected doctest",
-              expected: unquote(test.expr),
-              actual: "by raising #{inspect unquote(exception)}",
-              reason: "terminate",
-              instead: error ],
+              description: unquote(test.expr),
+              expected: "#{inspect unquote(exception)}",
+              reason: "raise",
+              actual: inspect(error) ],
             unquote(stack)
       end
     end
@@ -248,12 +248,12 @@ defmodule ExUnit.DocTest do
     rescue e ->
       quote do
         raise ExUnit.ExpectationError,
-            [ prelude: "Expected doctest's expression",
-              expected: unquote(expr),
-              actual: "successfully",
-              reason: "compile",
-              instead: unquote(Macro.escape e) ],
-            unquote(stack)
+          [ prelude: "Expected doctest",
+            description: unquote(expr),
+            expected: "successfully",
+            reason: "compile",
+            actual: unquote("** #{inspect e.__record__(:name)} #{e.message}") ],
+          unquote(stack)
       end
     end
   end