From 2b3a002a2a62ee5ef4767b4738456dedba88f780 Mon Sep 17 00:00:00 2001
From: Philippe Creux <pcreux@gmail.com>
Date: Thu, 15 Jun 2023 11:07:31 +0200
Subject: [PATCH] Improve error messages of assert_changes and
 assert_no_changes

---
 activesupport/CHANGELOG.md                             | 8 ++++++++
 activesupport/lib/active_support/testing/assertions.rb | 8 ++++----
 activesupport/test/test_case_test.rb                   | 2 +-
 3 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/activesupport/CHANGELOG.md b/activesupport/CHANGELOG.md
index 149a19e40b..27a3943e9c 100644
--- a/activesupport/CHANGELOG.md
+++ b/activesupport/CHANGELOG.md
@@ -1,3 +1,11 @@
+*   Improve error messages of `assert_changes` and `assert_no_changes`
+
+    `assert_changes` error messages now display objects with `.inspect` to make it easier
+    to differentiate nil from empty strings, strings from symbols, etc.
+    `assert_no_changes` error messages now surface the actual value.
+
+    *pcreux*
+
 *   Fix `#to_fs(:human_size)` to correctly work with negative numbers.
 
     *Earlopain*
diff --git a/activesupport/lib/active_support/testing/assertions.rb b/activesupport/lib/active_support/testing/assertions.rb
index a6634999dc..94c2374316 100644
--- a/activesupport/lib/active_support/testing/assertions.rb
+++ b/activesupport/lib/active_support/testing/assertions.rb
@@ -195,7 +195,7 @@ def assert_changes(expression, message = nil, from: UNTRACKED, to: UNTRACKED, &b
         retval = _assert_nothing_raised_or_warn("assert_changes", &block)
 
         unless from == UNTRACKED
-          error = "Expected change from #{from.inspect}, got #{before}"
+          error = "Expected change from #{from.inspect}, got #{before.inspect}"
           error = "#{message}.\n#{error}" if message
           assert from === before, error
         end
@@ -203,12 +203,12 @@ def assert_changes(expression, message = nil, from: UNTRACKED, to: UNTRACKED, &b
         after = exp.call
 
         error = "#{expression.inspect} didn't change"
-        error = "#{error}. It was already #{to}" if before == to
+        error = "#{error}. It was already #{to.inspect}" if before == to
         error = "#{message}.\n#{error}" if message
         refute_equal before, after, error
 
         unless to == UNTRACKED
-          error = "Expected change to #{to}, got #{after}\n"
+          error = "Expected change to #{to.inspect}, got #{after.inspect}\n"
           error = "#{message}.\n#{error}" if message
           assert to === after, error
         end
@@ -242,7 +242,7 @@ def assert_no_changes(expression, message = nil, from: UNTRACKED, &block)
         retval = _assert_nothing_raised_or_warn("assert_no_changes", &block)
 
         unless from == UNTRACKED
-          error = "Expected initial value of #{from.inspect}"
+          error = "Expected initial value of #{from.inspect}, got #{before.inspect}"
           error = "#{message}.\n#{error}" if message
           assert from === before, error
         end
diff --git a/activesupport/test/test_case_test.rb b/activesupport/test/test_case_test.rb
index 5a30e9d887..dc2c277299 100644
--- a/activesupport/test/test_case_test.rb
+++ b/activesupport/test/test_case_test.rb
@@ -331,7 +331,7 @@ def test_assert_no_changes_with_from_option_with_nil
         @object.increment
       end
     end
-    assert_equal "Expected initial value of nil", error.message
+    assert_equal "Expected initial value of nil, got 0", error.message
   end
 
   def test_assert_no_changes_with_from_and_case_operator