fix: align std.assertEqual failure messages

sjsonnet/src/sjsonnet/stdlib/TypeModule.scala

@@ -137,13 +137,14 @@ object TypeModule extends AbstractFunctionModule {
     def evalRhs(v1: Eval, v2: Eval, ev: EvalScope, pos: Position): Val = {
       val a = v1.value
       val b = v2.value
-      // Use structural equality first (avoids double materialization on success path)
+      // Use structural equality first (avoids double materialization on success path).
       if (ev.equal(a, b)) Val.True(pos)
       else {
-        // Only materialize on failure for the error message
-        val x1 = Materializer(a)(ev)
-        val x2 = Materializer(b)(ev)
-        Error.fail("std.assertEqual: " + x1 + " != " + x2)
+        // Match official std.jsonnet: strings are JSON-escaped, and non-strings are
+        // stringified through Jsonnet value rendering by the later concatenation.
+        val x1 = Materializer.stringify(a)(ev)
+        val x2 = Materializer.stringify(b)(ev)
+        Error.fail("Assertion failed. " + x1 + " != " + x2)
       }
     }
   }

sjsonnet/test/resources/go_test_suite/assert_equal4.jsonnet.golden

@@ -1,2 +1,2 @@
-sjsonnet.Error: [std.assertEqual] {"x":1} != {"x":2}
+sjsonnet.Error: [std.assertEqual] Assertion failed. {"x": 1} != {"x": 2}
     at [<root>].(assert_equal4.jsonnet:1:16)

sjsonnet/test/resources/go_test_suite/assert_equal5.jsonnet.golden

@@ -1,2 +1,2 @@
-sjsonnet.Error: [std.assertEqual] "\n " != "\n"
+sjsonnet.Error: [std.assertEqual] Assertion failed. "\n " != "\n"
     at [<root>].(assert_equal5.jsonnet:1:16)

sjsonnet/test/resources/go_test_suite/assert_equal6.jsonnet.golden

@@ -1,2 +1,2 @@
-sjsonnet.Error: [std.assertEqual] "\u001b[31m" != ""
+sjsonnet.Error: [std.assertEqual] Assertion failed. "\u001b[31m" != ""
     at [<root>].(assert_equal6.jsonnet:1:16)

sjsonnet/test/resources/new_test_suite/error.assert_equal_official_message.jsonnet

@@ -0,0 +1 @@
+std.assertEqual({x: 1}, {x: 2})

sjsonnet/test/resources/new_test_suite/error.assert_equal_official_message.jsonnet.golden

@@ -0,0 +1,2 @@
+sjsonnet.Error: [std.assertEqual] Assertion failed. {"x": 1} != {"x": 2}
+    at [<root>].(error.assert_equal_official_message.jsonnet:1:16)

sjsonnet/test/resources/test_suite/error.assert_equal_obj.jsonnet.golden

@@ -1,2 +1,2 @@
-sjsonnet.Error: [std.assertEqual] {"a":1} != {"b":1}
+sjsonnet.Error: [std.assertEqual] Assertion failed. {"a": 1} != {"b": 1}
     at [<root>].(error.assert_equal_obj.jsonnet:17:16)

sjsonnet/test/resources/test_suite/error.assert_equal_str.jsonnet.golden

@@ -1,2 +1,2 @@
-sjsonnet.Error: [std.assertEqual] "one\ntwo" != "three\nfour\n"
+sjsonnet.Error: [std.assertEqual] Assertion failed. "one\ntwo" != "three\nfour\n"
     at [<root>].(error.assert_equal_str.jsonnet:17:16)

sjsonnet/test/resources/test_suite/error.sanity.jsonnet.golden

@@ -1,2 +1,2 @@
-sjsonnet.Error: [std.assertEqual] 1 != 2
+sjsonnet.Error: [std.assertEqual] Assertion failed. 1 != 2
     at [<root>].(error.sanity.jsonnet:17:16)