Merge pull request #3726 from whatyouhide/better-assert-raise-messages

Better assert raise messages

Author: josevalim

lib/ex_unit/lib/ex_unit/assertions.ex

@@ -392,8 +392,11 @@ defmodule ExUnit.Assertions do
       Regex.regex?(message) -> Exception.message(error) =~ message
     end
 
-    msg = "Wrong message for #{inspect exception}. " <>
-          "Expected #{inspect message}, got #{inspect Exception.message(error)}"
+    msg = "Wrong message for #{inspect exception}\n" <>
+          "Expected:\n" <>
+          "  #{inspect message}\n" <>
+          "Got:\n" <>
+          "  #{inspect Exception.message(error)}"
     assert is_match, message: msg
 
     error

lib/ex_unit/test/ex_unit/assertions_test.exs

@@ -336,6 +336,32 @@ defmodule ExUnit.AssertionsTest do
       "Expected exception SyntaxError but got FunctionClauseError (no function clause matching in :lists.flatten/1)" = error.message
   end
 
+  test "assert raise comparing messages (for equality)" do
+    assert_raise RuntimeError, "foo", fn ->
+      raise RuntimeError, "bar"
+    end
+  rescue
+    error in [ExUnit.AssertionError] ->
+      "Wrong message for RuntimeError" <>
+      "\nExpected:" <>
+      "\n  \"foo\"" <>
+      "\nGot:" <>
+      "\n  \"bar\"" = error.message
+  end
+
+  test "assert raise comparing messages (with a regex)" do
+    assert_raise RuntimeError, ~r/ba[zk]/, fn ->
+      raise RuntimeError, "bar"
+    end
+  rescue
+    error in [ExUnit.AssertionError] ->
+      "Wrong message for RuntimeError" <>
+      "\nExpected:" <>
+      "\n  ~r/ba[zk]/" <>
+      "\nGot:" <>
+      "\n  \"bar\"" = error.message
+  end
+
   test "assert greater than operator" do
     true = assert 2 > 1
   end