pkg/test_runner/test/update_errors_test.dart - sdk - Git at Google

 // Copyright (c) 2019, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.

 // ignore_for_file: unnecessary_string_escapes

 import 'dart:math' as math;

 import 'package:expect/expect.dart';
 import 'package:test_runner/src/static_error.dart';
 import 'package:test_runner/src/update_errors.dart';

 import 'utils.dart';

 // Note: This test file validates how some of the special markers used by the
 // test runner are parsed. But this test is also run *by* that same test
 // runner, and we don't want it to see the markers inside the string literals
 // here as significant, so we obfuscate them using seemingly-pointless string
 // escapes here like `\/`.

 void main() {
   // Inserts single-front end errors.
   expectUpdate(
     """
 int i = "bad";

 int another = "wrong";

 int third = "boo";
 """,
     errors: [
       makeError(line: 1, column: 9, length: 5, analyzerError: "some.error"),
       makeError(line: 3, column: 15, length: 7, cfeError: "Bad."),
       makeError(line: 5, column: 13, length: 5, webError: "Web.\nError."),
     ],
     expected: """
 int i = "bad";
 /\/      ^^^^^
 /\/ [analyzer] some.error

 int another = "wrong";
 /\/            ^^^^^^^
 /\/ [cfe] Bad.

 int third = "boo";
 /\/          ^^^^^
 /\/ [web] Web.
 /\/ Error.
 """,
   );

   // Inserts errors for multiple front ends.
   expectUpdate(
     """
 int i = "bad";

 int another = "wrong";

 int third = "boo";

 int last = "oops";
 """,
     errors: [
       makeError(line: 1, column: 9, length: 5, analyzerError: "some.error"),
       makeError(line: 1, column: 9, length: 5, cfeError: "Bad."),
       makeError(line: 3, column: 15, length: 7, cfeError: "Another bad."),
       makeError(line: 3, column: 15, length: 7, webError: "Web.\nError."),
       makeError(line: 5, column: 13, length: 5, analyzerError: "third.error"),
       makeError(line: 5, column: 13, length: 5, webError: "Web error."),
       makeError(line: 7, column: 12, length: 6, analyzerError: "last.error"),
       makeError(line: 7, column: 12, length: 6, cfeError: "Final.\nError."),
       makeError(line: 7, column: 12, length: 6, webError: "Web error."),
     ],
     expected: """
 int i = "bad";
 /\/      ^^^^^
 /\/ [analyzer] some.error
 /\/ [cfe] Bad.

 int another = "wrong";
 /\/            ^^^^^^^
 /\/ [cfe] Another bad.
 /\/ [web] Web.
 /\/ Error.

 int third = "boo";
 /\/          ^^^^^
 /\/ [analyzer] third.error
 /\/ [web] Web error.

 int last = "oops";
 /\/         ^^^^^^
 /\/ [analyzer] last.error
 /\/ [cfe] Final.
 /\/ Error.
 /\/ [web] Web error.
 """,
   );

   // Removes only analyzer errors.
   expectUpdate(
     """
 int i = "bad";
 /\/      ^^^^^
 /\/ [analyzer] some.error

 int another = "wrong";
 /\/            ^^^^^^^
 /\/ [cfe] Bad.

 int third = "boo";
 /\/          ^^^^^
 /\/ [analyzer] an.error
 /\/ [cfe] Wrong.
 """,
     remove: {ErrorSource.analyzer},
     expected: """
 int i = "bad";

 int another = "wrong";
 /\/            ^^^^^^^
 /\/ [cfe] Bad.

 int third = "boo";
 /\/          ^^^^^
 /\/ [cfe] Wrong.
 """,
   );

   // Removes only CFE errors.
   expectUpdate(
     """
 int i = "bad";
 /\/      ^^^^^
 /\/ [analyzer] some.error

 int another = "wrong";
 /\/            ^^^^^^^
 /\/ [cfe] Bad.

 int third = "boo";
 /\/          ^^^^^
 /\/ [analyzer] an.error
 /\/ [cfe] Wrong.
 """,
     remove: {ErrorSource.cfe},
     expected: """
 int i = "bad";
 /\/      ^^^^^
 /\/ [analyzer] some.error

 int another = "wrong";

 int third = "boo";
 /\/          ^^^^^
 /\/ [analyzer] an.error
 """,
   );

   // Removes only web errors.
   expectUpdate(
     """
 int i = "bad";
 /\/      ^^^^^
 /\/ [analyzer] some.error

 int another = "wrong";
 /\/            ^^^^^^^
 /\/ [web] Bad.

 int third = "boo";
 /\/          ^^^^^
 /\/ [cfe] Error.
 /\/ [web] Wrong.
 """,
     remove: {ErrorSource.web},
     expected: """
 int i = "bad";
 /\/      ^^^^^
 /\/ [analyzer] some.error

 int another = "wrong";

 int third = "boo";
 /\/          ^^^^^
 /\/ [cfe] Error.
 """,
   );

   // Removes multiple error sources.
   expectUpdate(
     """
 int i = "bad";
 /\/      ^^^^^
 /\/ [analyzer] some.error
 /\/ [cfe] CFE error.

 int another = "wrong";
 /\/            ^^^^^^^
 /\/ [web] Bad.

 int third = "boo";
 /\/          ^^^^^
 /\/ [analyzer] another.error
 /\/ [cfe] Error.
 /\/ [web] Wrong.
 """,
     remove: {ErrorSource.analyzer, ErrorSource.web},
     expected: """
 int i = "bad";
 /\/      ^^^^^
 /\/ [cfe] CFE error.

 int another = "wrong";

 int third = "boo";
 /\/          ^^^^^
 /\/ [cfe] Error.
 """,
   );

   // Preserves previous error's indentation if possible.
   expectUpdate(
     """
 int i = "bad";
     /\/    ^^
     /\/ [analyzer] previous.error
 """,
     errors: [
       makeError(line: 1, column: 9, length: 5, analyzerError: "updated.error"),
       makeError(
         line: 1,
         column: 9,
         length: 5,
         cfeError: "Long.\nError.\nMessage.",
       ),
     ],
     expected: """
 int i = "bad";
     /\/  ^^^^^
     /\/ [analyzer] updated.error
     /\/ [cfe] Long.
     /\/ Error.
     /\/ Message.
 """,
   );

   // Uses previous line's indentation if there was no existing error
   // expectation.
   expectUpdate(
     """
 main() {
   int i = "bad";
 }
 """,
     errors: [
       makeError(line: 2, column: 11, length: 5, analyzerError: "updated.error"),
     ],
     expected: """
 main() {
   int i = "bad";
   /\/      ^^^^^
   /\/ [analyzer] updated.error
 }
 """,
   );

   // Discards previous error indentation if it would collide with carets.
   expectUpdate(
     """
 // This fits:
 int i = "bad";
       /\/    ^^
       /\/ [analyzer] previous.error

 // This does not:
 int j = "bad";
        /\/    ^^
        /\/ [analyzer] previous.error
 """,
     errors: [
       makeError(line: 2, column: 9, length: 5, cfeError: "Error."),
       makeError(line: 7, column: 9, length: 5, cfeError: "Error."),
     ],
     expected: """
 // This fits:
 int i = "bad";
       /\/^^^^^
       /\/ [cfe] Error.

 // This does not:
 int j = "bad";
 /\/      ^^^^^
 /\/ [cfe] Error.
 """,
   );

   // Uses explicit location if indenting based on preceding code would collide
   // with carets.
   expectUpdate(
     """
 main() {
   ["bad"];
 }
 """,
     errors: [makeError(line: 2, column: 4, length: 5, cfeError: "Error.")],
     expected: """
 main() {
   ["bad"];
   /\/ [error column 4, length 5]
   /\/ [cfe] Error.
 }
 """,
   );

   // Uses length one if there's no length.
   expectUpdate(
     """
 int i = "bad";
 """,
     errors: [makeError(line: 1, column: 9, cfeError: "Error.")],
     expected: """
 int i = "bad";
 /\/      ^
 /\/ [cfe] Error.
 """,
   );

   // Explicit error location handles null length.
   expectUpdate(
     """
 int i =
 "bad";
 """,
     errors: [makeError(line: 2, column: 1, cfeError: "Error.")],
     expected: """
 int i =
 "bad";
 /\/ [error column 1]
 /\/ [cfe] Error.
 """,
   );

   // Handles shifted line numbers in explicit error locations.
   // Note that the reported line is line 6, but the output is line 3 to take
   // into account the three removed lines.
   expectUpdate(
     """
 main() {
 /\/ ^^
 /\/ [analyzer] ERROR.CODE
 /\/ [cfe] Error.
 }
 Error here;
 """,
     errors: [
       makeError(line: 6, column: 1, length: 5, analyzerError: "NEW.ERROR"),
       makeError(line: 6, column: 2, length: 3, cfeError: "Error."),
     ],
     expected: """
 main() {
 }
 Error here;
 /\/ [error column 1, length 5]
 /\/ [analyzer] NEW.ERROR
 /\/ [error column 2, length 3]
 /\/ [cfe] Error.
 """,
   );

   // Inserts a blank line if a subsequent line comment would become part of the
   // error message.
   expectUpdate(
     """
 int i = "bad";
 // Line comment.
 """,
     errors: [makeError(line: 1, column: 9, length: 5, cfeError: "Wrong.")],
     expected: """
 int i = "bad";
 /\/      ^^^^^
 /\/ [cfe] Wrong.

 // Line comment.
 """,
   );

   // Inserts a blank line if a subsequent line comment would become part of the
   // error message.
   expectUpdate(
     """
 int i = "bad";
 // Line comment.
 """,
     errors: [
       makeError(line: 1, column: 9, length: 5, analyzerError: "ERR.CODE"),
     ],
     expected: """
 int i = "bad";
 /\/      ^^^^^
 /\/ [analyzer] ERR.CODE

 // Line comment.
 """,
   );

   // Multiple errors on the same line are ordered by column then length.
   expectUpdate(
     """
 someBadCode();
 """,
     errors: [
       makeError(line: 1, column: 9, length: 5, cfeError: "Wrong 1."),
       makeError(line: 1, column: 9, length: 4, cfeError: "Wrong 2."),
       makeError(line: 1, column: 6, length: 3, cfeError: "Wrong 3."),
       makeError(line: 1, column: 5, length: 5, cfeError: "Wrong 4."),
     ],
     expected: """
 someBadCode();
 /\/  ^^^^^
 /\/ [cfe] Wrong 4.
 /\/   ^^^
 /\/ [cfe] Wrong 3.
 /\/      ^^^^
 /\/ [cfe] Wrong 2.
 /\/      ^^^^^
 /\/ [cfe] Wrong 1.
 """,
   );

   // Shared locations between errors with and without length.
   expectUpdate(
     """
 someBadCode(arg);

 moreBadCode(arg);
 """,
     errors: [
       makeError(line: 1, column: 13, length: 3, analyzerError: "Error.CODE"),
       makeError(line: 1, column: 13, cfeError: "Wrong 1."),
       makeError(line: 3, column: 13, cfeError: "Wrong 2."),
       makeError(line: 3, column: 13, length: 3, webError: "Web error."),
     ],
     expected: """
 someBadCode(arg);
 /\/          ^^^
 /\/ [analyzer] Error.CODE
 /\/ [cfe] Wrong 1.

 moreBadCode(arg);
 /\/          ^^^
 /\/ [web] Web error.
 /\/ [cfe] Wrong 2.
 """,
   );

   // Doesn't crash with RangeError.
   expectUpdate(
     """
 x
 /\/ [error line 1, column 1, length 0]
 /\/ [cfe] Whatever""",
     errors: [makeError(line: 1, column: 1, length: 0, cfeError: "Foo")],
     expected: """
 x
 /\/ [error column 1]
 /\/ [cfe] Foo""",
   );

   contextMessages();
   regression();
 }

 void contextMessages() {
   // Inserts context messages.
   expectUpdate(
     """
 int i = "bad";

 int another = "wrong";

 int third = "boo";
 """,
     errors: [
       makeError(
         line: 3,
         column: 15,
         length: 7,
         analyzerError: "some.error",
         context: [
           makeError(
             line: 1,
             column: 9,
             length: 5,
             contextError: "Analyzer context.",
           ),
           makeError(
             line: 5,
             column: 13,
             length: 5,
             contextError: "More context.",
           ),
         ],
       ),
       makeError(
         line: 3,
         column: 15,
         length: 7,
         cfeError: "CFE error.",
         context: [
           makeError(
             line: 1,
             column: 9,
             length: 5,
             contextError: "CFE context.",
           ),
         ],
       ),
     ],
     remove: {ErrorSource.analyzer},
     includeContext: true,
     expected: """
 int i = "bad";
 /\/      ^^^^^
 /\/ [context 1] Analyzer context.
 /\/ [context 2] CFE context.

 int another = "wrong";
 /\/            ^^^^^^^
 /\/ [analyzer 1] some.error
 /\/ [cfe 2] CFE error.

 int third = "boo";
 /\/          ^^^^^
 /\/ [context 1] More context.
 """,
   );

   // Removes context messages for removed errors.
   expectUpdate(
     """
 int i = "bad";
 /\/      ^^^^^
 /\/ [context 1] Analyzer context.
 /\/ [context 2] CFE context.

 int another = "wrong";
 /\/            ^^^^^^^
 /\/ [analyzer 1] some.error
 /\/ [cfe 2] CFE error.

 int third = "boo";
 /\/          ^^^^^
 /\/ [context 1] More context.
 """,
     remove: {ErrorSource.analyzer},
     includeContext: true,
     expected: """
 int i = "bad";
 /\/      ^^^^^
 /\/ [context 1] CFE context.

 int another = "wrong";
 /\/            ^^^^^^^
 /\/ [cfe 1] CFE error.

 int third = "boo";
 """,
   );

   // Discards context messages when not told to include them.
   expectUpdate(
     """
 int i = "bad";

 int another = "wrong";

 int third = "boo";
 """,
     errors: [
       makeError(
         line: 3,
         column: 15,
         length: 7,
         analyzerError: "some.error",
         context: [
           makeError(
             line: 1,
             column: 9,
             length: 5,
             contextError: "Analyzer context.",
           ),
           makeError(
             line: 5,
             column: 13,
             length: 5,
             contextError: "More context.",
           ),
         ],
       ),
       makeError(
         line: 3,
         column: 15,
         length: 7,
         cfeError: "CFE error.",
         context: [
           makeError(
             line: 1,
             column: 9,
             length: 5,
             contextError: "CFE context.",
           ),
         ],
       ),
     ],
     includeContext: false,
     expected: """
 int i = "bad";

 int another = "wrong";
 /\/            ^^^^^^^
 /\/ [analyzer] some.error
 /\/ [cfe] CFE error.

 int third = "boo";
 """,
   );

   // Discards existing context messages when not told to include them.
   expectUpdate(
     """
 int i = "bad";
 /\/      ^^^^^
 /\/ [context 1] CFE context.

 int another = "wrong";
 /\/            ^^^^^^^
 /\/ [cfe 1] CFE error.

 int third = "boo";
 """,
     errors: [
       makeError(
         line: 5,
         column: 15,
         length: 7,
         analyzerError: "some.error",
         context: [
           makeError(
             line: 1,
             column: 9,
             length: 5,
             contextError: "Analyzer context.",
           ),
           makeError(
             line: 7,
             column: 13,
             length: 5,
             contextError: "More context.",
           ),
         ],
       ),
     ],
     remove: {ErrorSource.analyzer},
     includeContext: false,
     expected: """
 int i = "bad";

 int another = "wrong";
 /\/            ^^^^^^^
 /\/ [analyzer] some.error
 /\/ [cfe] CFE error.

 int third = "boo";
 """,
   );
 }

 void regression() {
   // https://github.com/dart-lang/sdk/issues/37990.
   expectUpdate(
     """
 int get xx => 3;
 int get yy => 3;

 class A {
   void test() {
     xx = 1;
 /\/  ^^^^^^^^^^^^^^
 /\/ [cfe] unspecified
 /\/  ^^^^^^^^^^^^^^
 /\/ [analyzer] unspecified


     yy(4);
 /\/  ^^^^^^^^^^^^^^
 /\/ [cfe] unspecified
 /\/  ^^^^^^^^^^^^^^
 /\/ [analyzer] unspecified

   }
 }
 """,
     remove: {ErrorSource.cfe},
     errors: [
       makeError(
         line: 6,
         column: 5,
         length: 14,
         cfeError: "Setter not found: 'xx'.",
       ),
       makeError(
         line: 16,
         column: 7,
         cfeError: "The method 'call' isn't defined for the class 'int'.",
       ),
     ],
     expected: """
 int get xx => 3;
 int get yy => 3;

 class A {
   void test() {
     xx = 1;
 /\/  ^^^^^^^^^^^^^^
 /\/ [analyzer] unspecified
 /\/ [cfe] Setter not found: 'xx'.


     yy(4);
 /\/  ^^^^^^^^^^^^^^
 /\/ [analyzer] unspecified
 /\/    ^
 /\/ [cfe] The method 'call' isn't defined for the class 'int'.

   }
 }
 """,
   );
 }

 void expectUpdate(
   String original, {
   List<StaticError>? errors,
   Set<ErrorSource>? remove,
   bool? includeContext,
   String? expected,
 }) {
   errors ??= const [];
   remove ??= ErrorSource.all.toSet();
   includeContext ??= false;

   var actual = updateErrorExpectations(
     'some_test.dart',
     original,
     errors,
     remove: remove,
     includeContext: includeContext,
   );
   if (actual != expected) {
     // Not using Expect.equals() because the diffs it shows aren't helpful for
     // strings this large.
     var actualLines = actual.split("\n");
     var expectedLines = expected!.split("\n");

     // Figure out which leading lines do match so we can ignore those and
     // highlight the offending ones.
     var matchingActual = <int>{};
     var matchingExpected = <int>{};
     for (
       var i = 0;
       i < math.min(actualLines.length, expectedLines.length);
       i++
     ) {
       if (actualLines[i] != expectedLines[i]) break;
       matchingActual.add(i);
       matchingExpected.add(i);
     }

     // Find which trailing lines are the same so we can hide those too.
     for (
       var i = 0;
       i < math.min(actualLines.length, expectedLines.length);
       i++
     ) {
       // Count backwards from the ends of each list.
       var actualIndex = actualLines.length - i - 1;
       var expectedIndex = expectedLines.length - i - 1;
       if (actualLines[actualIndex] != expectedLines[expectedIndex]) break;
       matchingActual.add(actualIndex);
       matchingExpected.add(expectedIndex);
     }

     var buffer = StringBuffer();
     void writeLine(int index, String line, Set<int> matchingLines) {
       // Only show the line if it was different from the expectation.
       if (matchingLines.contains(index)) {
         buffer.writeln("    : $line");
       } else {
         buffer.writeln("${(index + 1).toString().padLeft(4)}: $line");
       }
     }

     buffer.writeln("Output did not match expectation. Expected:");
     for (var i = 0; i < expectedLines.length; i++) {
       writeLine(i, expectedLines[i], matchingExpected);
     }

     buffer.writeln();
     buffer.writeln("Was:");
     for (var i = 0; i < actualLines.length; i++) {
       writeLine(i, actualLines[i], matchingActual);
     }

     Expect.fail(buffer.toString());
   }
 }
	// Copyright (c) 2019, the Dart project authors. Please see the AUTHORS file
	// for details. All rights reserved. Use of this source code is governed by a
	// BSD-style license that can be found in the LICENSE file.

	// ignore_for_file: unnecessary_string_escapes

	import 'dart:math' as math;

	import 'package:expect/expect.dart';
	import 'package:test_runner/src/static_error.dart';
	import 'package:test_runner/src/update_errors.dart';

	import 'utils.dart';

	// Note: This test file validates how some of the special markers used by the
	// test runner are parsed. But this test is also run by that same test
	// runner, and we don't want it to see the markers inside the string literals
	// here as significant, so we obfuscate them using seemingly-pointless string
	// escapes here like `\/`.

	void main() {
	// Inserts single-front end errors.
	expectUpdate(
	"""
	int i = "bad";

	int another = "wrong";

	int third = "boo";
	""",
	errors: [
	makeError(line: 1, column: 9, length: 5, analyzerError: "some.error"),
	makeError(line: 3, column: 15, length: 7, cfeError: "Bad."),
	makeError(line: 5, column: 13, length: 5, webError: "Web.\nError."),
	],
	expected: """
	int i = "bad";
	/\/ ^^^^^
	/\/ [analyzer] some.error

	int another = "wrong";
	/\/ ^^^^^^^
	/\/ [cfe] Bad.

	int third = "boo";
	/\/ ^^^^^
	/\/ [web] Web.
	/\/ Error.
	""",
	);

	// Inserts errors for multiple front ends.
	expectUpdate(
	"""
	int i = "bad";

	int another = "wrong";

	int third = "boo";

	int last = "oops";
	""",
	errors: [
	makeError(line: 1, column: 9, length: 5, analyzerError: "some.error"),
	makeError(line: 1, column: 9, length: 5, cfeError: "Bad."),
	makeError(line: 3, column: 15, length: 7, cfeError: "Another bad."),
	makeError(line: 3, column: 15, length: 7, webError: "Web.\nError."),
	makeError(line: 5, column: 13, length: 5, analyzerError: "third.error"),
	makeError(line: 5, column: 13, length: 5, webError: "Web error."),
	makeError(line: 7, column: 12, length: 6, analyzerError: "last.error"),
	makeError(line: 7, column: 12, length: 6, cfeError: "Final.\nError."),
	makeError(line: 7, column: 12, length: 6, webError: "Web error."),
	],
	expected: """
	int i = "bad";
	/\/ ^^^^^
	/\/ [analyzer] some.error
	/\/ [cfe] Bad.

	int another = "wrong";
	/\/ ^^^^^^^
	/\/ [cfe] Another bad.
	/\/ [web] Web.
	/\/ Error.

	int third = "boo";
	/\/ ^^^^^
	/\/ [analyzer] third.error
	/\/ [web] Web error.

	int last = "oops";
	/\/ ^^^^^^
	/\/ [analyzer] last.error
	/\/ [cfe] Final.
	/\/ Error.
	/\/ [web] Web error.
	""",
	);

	// Removes only analyzer errors.
	expectUpdate(
	"""
	int i = "bad";
	/\/ ^^^^^
	/\/ [analyzer] some.error

	int another = "wrong";
	/\/ ^^^^^^^
	/\/ [cfe] Bad.

	int third = "boo";
	/\/ ^^^^^
	/\/ [analyzer] an.error
	/\/ [cfe] Wrong.
	""",
	remove: {ErrorSource.analyzer},
	expected: """
	int i = "bad";

	int another = "wrong";
	/\/ ^^^^^^^
	/\/ [cfe] Bad.

	int third = "boo";
	/\/ ^^^^^
	/\/ [cfe] Wrong.
	""",
	);

	// Removes only CFE errors.
	expectUpdate(
	"""
	int i = "bad";
	/\/ ^^^^^
	/\/ [analyzer] some.error

	int another = "wrong";
	/\/ ^^^^^^^
	/\/ [cfe] Bad.

	int third = "boo";
	/\/ ^^^^^
	/\/ [analyzer] an.error
	/\/ [cfe] Wrong.
	""",
	remove: {ErrorSource.cfe},
	expected: """
	int i = "bad";
	/\/ ^^^^^
	/\/ [analyzer] some.error

	int another = "wrong";

	int third = "boo";
	/\/ ^^^^^
	/\/ [analyzer] an.error
	""",
	);

	// Removes only web errors.
	expectUpdate(
	"""
	int i = "bad";
	/\/ ^^^^^
	/\/ [analyzer] some.error

	int another = "wrong";
	/\/ ^^^^^^^
	/\/ [web] Bad.

	int third = "boo";
	/\/ ^^^^^
	/\/ [cfe] Error.
	/\/ [web] Wrong.
	""",
	remove: {ErrorSource.web},
	expected: """
	int i = "bad";
	/\/ ^^^^^
	/\/ [analyzer] some.error

	int another = "wrong";

	int third = "boo";
	/\/ ^^^^^
	/\/ [cfe] Error.
	""",
	);

	// Removes multiple error sources.
	expectUpdate(
	"""
	int i = "bad";
	/\/ ^^^^^
	/\/ [analyzer] some.error
	/\/ [cfe] CFE error.

	int another = "wrong";
	/\/ ^^^^^^^
	/\/ [web] Bad.

	int third = "boo";
	/\/ ^^^^^
	/\/ [analyzer] another.error
	/\/ [cfe] Error.
	/\/ [web] Wrong.
	""",
	remove: {ErrorSource.analyzer, ErrorSource.web},
	expected: """
	int i = "bad";
	/\/ ^^^^^
	/\/ [cfe] CFE error.

	int another = "wrong";

	int third = "boo";
	/\/ ^^^^^
	/\/ [cfe] Error.
	""",
	);

	// Preserves previous error's indentation if possible.
	expectUpdate(
	"""
	int i = "bad";
	/\/ ^^
	/\/ [analyzer] previous.error
	""",
	errors: [
	makeError(line: 1, column: 9, length: 5, analyzerError: "updated.error"),
	makeError(
	line: 1,
	column: 9,
	length: 5,
	cfeError: "Long.\nError.\nMessage.",
	),
	],
	expected: """
	int i = "bad";
	/\/ ^^^^^
	/\/ [analyzer] updated.error
	/\/ [cfe] Long.
	/\/ Error.
	/\/ Message.
	""",
	);

	// Uses previous line's indentation if there was no existing error
	// expectation.
	expectUpdate(
	"""
	main() {
	int i = "bad";
	}
	""",
	errors: [
	makeError(line: 2, column: 11, length: 5, analyzerError: "updated.error"),
	],
	expected: """
	main() {
	int i = "bad";
	/\/ ^^^^^
	/\/ [analyzer] updated.error
	}
	""",
	);

	// Discards previous error indentation if it would collide with carets.
	expectUpdate(
	"""
	// This fits:
	int i = "bad";
	/\/ ^^
	/\/ [analyzer] previous.error

	// This does not:
	int j = "bad";
	/\/ ^^
	/\/ [analyzer] previous.error
	""",
	errors: [
	makeError(line: 2, column: 9, length: 5, cfeError: "Error."),
	makeError(line: 7, column: 9, length: 5, cfeError: "Error."),
	],
	expected: """
	// This fits:
	int i = "bad";
	/\/^^^^^
	/\/ [cfe] Error.

	// This does not:
	int j = "bad";
	/\/ ^^^^^
	/\/ [cfe] Error.
	""",
	);

	// Uses explicit location if indenting based on preceding code would collide
	// with carets.
	expectUpdate(
	"""
	main() {
	["bad"];
	}
	""",
	errors: [makeError(line: 2, column: 4, length: 5, cfeError: "Error.")],
	expected: """
	main() {
	["bad"];
	/\/ [error column 4, length 5]
	/\/ [cfe] Error.
	}
	""",
	);

	// Uses length one if there's no length.
	expectUpdate(
	"""
	int i = "bad";
	""",
	errors: [makeError(line: 1, column: 9, cfeError: "Error.")],
	expected: """
	int i = "bad";
	/\/ ^
	/\/ [cfe] Error.
	""",
	);

	// Explicit error location handles null length.
	expectUpdate(
	"""
	int i =
	"bad";
	""",
	errors: [makeError(line: 2, column: 1, cfeError: "Error.")],
	expected: """
	int i =
	"bad";
	/\/ [error column 1]
	/\/ [cfe] Error.
	""",
	);

	// Handles shifted line numbers in explicit error locations.
	// Note that the reported line is line 6, but the output is line 3 to take
	// into account the three removed lines.
	expectUpdate(
	"""
	main() {
	/\/ ^^
	/\/ [analyzer] ERROR.CODE
	/\/ [cfe] Error.
	}
	Error here;
	""",
	errors: [
	makeError(line: 6, column: 1, length: 5, analyzerError: "NEW.ERROR"),
	makeError(line: 6, column: 2, length: 3, cfeError: "Error."),
	],
	expected: """
	main() {
	}
	Error here;
	/\/ [error column 1, length 5]
	/\/ [analyzer] NEW.ERROR
	/\/ [error column 2, length 3]
	/\/ [cfe] Error.
	""",
	);

	// Inserts a blank line if a subsequent line comment would become part of the
	// error message.
	expectUpdate(
	"""
	int i = "bad";
	// Line comment.
	""",
	errors: [makeError(line: 1, column: 9, length: 5, cfeError: "Wrong.")],
	expected: """
	int i = "bad";
	/\/ ^^^^^
	/\/ [cfe] Wrong.

	// Line comment.
	""",
	);

	// Inserts a blank line if a subsequent line comment would become part of the
	// error message.
	expectUpdate(
	"""
	int i = "bad";
	// Line comment.
	""",
	errors: [
	makeError(line: 1, column: 9, length: 5, analyzerError: "ERR.CODE"),
	],
	expected: """
	int i = "bad";
	/\/ ^^^^^
	/\/ [analyzer] ERR.CODE

	// Line comment.
	""",
	);

	// Multiple errors on the same line are ordered by column then length.
	expectUpdate(
	"""
	someBadCode();
	""",
	errors: [
	makeError(line: 1, column: 9, length: 5, cfeError: "Wrong 1."),
	makeError(line: 1, column: 9, length: 4, cfeError: "Wrong 2."),
	makeError(line: 1, column: 6, length: 3, cfeError: "Wrong 3."),
	makeError(line: 1, column: 5, length: 5, cfeError: "Wrong 4."),
	],
	expected: """
	someBadCode();
	/\/ ^^^^^
	/\/ [cfe] Wrong 4.
	/\/ ^^^
	/\/ [cfe] Wrong 3.
	/\/ ^^^^
	/\/ [cfe] Wrong 2.
	/\/ ^^^^^
	/\/ [cfe] Wrong 1.
	""",
	);

	// Shared locations between errors with and without length.
	expectUpdate(
	"""
	someBadCode(arg);

	moreBadCode(arg);
	""",
	errors: [
	makeError(line: 1, column: 13, length: 3, analyzerError: "Error.CODE"),
	makeError(line: 1, column: 13, cfeError: "Wrong 1."),
	makeError(line: 3, column: 13, cfeError: "Wrong 2."),
	makeError(line: 3, column: 13, length: 3, webError: "Web error."),
	],
	expected: """
	someBadCode(arg);
	/\/ ^^^
	/\/ [analyzer] Error.CODE
	/\/ [cfe] Wrong 1.

	moreBadCode(arg);
	/\/ ^^^
	/\/ [web] Web error.
	/\/ [cfe] Wrong 2.
	""",
	);

	// Doesn't crash with RangeError.
	expectUpdate(
	"""
	x
	/\/ [error line 1, column 1, length 0]
	/\/ [cfe] Whatever""",
	errors: [makeError(line: 1, column: 1, length: 0, cfeError: "Foo")],
	expected: """
	x
	/\/ [error column 1]
	/\/ [cfe] Foo""",
	);

	contextMessages();
	regression();
	}

	void contextMessages() {
	// Inserts context messages.
	expectUpdate(
	"""
	int i = "bad";

	int another = "wrong";

	int third = "boo";
	""",
	errors: [
	makeError(
	line: 3,
	column: 15,
	length: 7,
	analyzerError: "some.error",
	context: [
	makeError(
	line: 1,
	column: 9,
	length: 5,
	contextError: "Analyzer context.",
	),
	makeError(
	line: 5,
	column: 13,
	length: 5,
	contextError: "More context.",
	),
	],
	),
	makeError(
	line: 3,
	column: 15,
	length: 7,
	cfeError: "CFE error.",
	context: [
	makeError(
	line: 1,
	column: 9,
	length: 5,
	contextError: "CFE context.",
	),
	],
	),
	],
	remove: {ErrorSource.analyzer},
	includeContext: true,
	expected: """
	int i = "bad";
	/\/ ^^^^^
	/\/ [context 1] Analyzer context.
	/\/ [context 2] CFE context.

	int another = "wrong";
	/\/ ^^^^^^^
	/\/ [analyzer 1] some.error
	/\/ [cfe 2] CFE error.

	int third = "boo";
	/\/ ^^^^^
	/\/ [context 1] More context.
	""",
	);

	// Removes context messages for removed errors.
	expectUpdate(
	"""
	int i = "bad";
	/\/ ^^^^^
	/\/ [context 1] Analyzer context.
	/\/ [context 2] CFE context.

	int another = "wrong";
	/\/ ^^^^^^^
	/\/ [analyzer 1] some.error
	/\/ [cfe 2] CFE error.

	int third = "boo";
	/\/ ^^^^^
	/\/ [context 1] More context.
	""",
	remove: {ErrorSource.analyzer},
	includeContext: true,
	expected: """
	int i = "bad";
	/\/ ^^^^^
	/\/ [context 1] CFE context.

	int another = "wrong";
	/\/ ^^^^^^^
	/\/ [cfe 1] CFE error.

	int third = "boo";
	""",
	);

	// Discards context messages when not told to include them.
	expectUpdate(
	"""
	int i = "bad";

	int another = "wrong";

	int third = "boo";
	""",
	errors: [
	makeError(
	line: 3,
	column: 15,
	length: 7,
	analyzerError: "some.error",
	context: [
	makeError(
	line: 1,
	column: 9,
	length: 5,
	contextError: "Analyzer context.",
	),
	makeError(
	line: 5,
	column: 13,
	length: 5,
	contextError: "More context.",
	),
	],
	),
	makeError(
	line: 3,
	column: 15,
	length: 7,
	cfeError: "CFE error.",
	context: [
	makeError(
	line: 1,
	column: 9,
	length: 5,
	contextError: "CFE context.",
	),
	],
	),
	],
	includeContext: false,
	expected: """
	int i = "bad";

	int another = "wrong";
	/\/ ^^^^^^^
	/\/ [analyzer] some.error
	/\/ [cfe] CFE error.

	int third = "boo";
	""",
	);

	// Discards existing context messages when not told to include them.
	expectUpdate(
	"""
	int i = "bad";
	/\/ ^^^^^
	/\/ [context 1] CFE context.

	int another = "wrong";
	/\/ ^^^^^^^
	/\/ [cfe 1] CFE error.

	int third = "boo";
	""",
	errors: [
	makeError(
	line: 5,
	column: 15,
	length: 7,
	analyzerError: "some.error",
	context: [
	makeError(
	line: 1,
	column: 9,
	length: 5,
	contextError: "Analyzer context.",
	),
	makeError(
	line: 7,
	column: 13,
	length: 5,
	contextError: "More context.",
	),
	],
	),
	],
	remove: {ErrorSource.analyzer},
	includeContext: false,
	expected: """
	int i = "bad";

	int another = "wrong";
	/\/ ^^^^^^^
	/\/ [analyzer] some.error
	/\/ [cfe] CFE error.

	int third = "boo";
	""",
	);
	}

	void regression() {
	// https://github.com/dart-lang/sdk/issues/37990.
	expectUpdate(
	"""
	int get xx => 3;
	int get yy => 3;

	class A {
	void test() {
	xx = 1;
	/\/ ^^^^^^^^^^^^^^
	/\/ [cfe] unspecified
	/\/ ^^^^^^^^^^^^^^
	/\/ [analyzer] unspecified


	yy(4);
	/\/ ^^^^^^^^^^^^^^
	/\/ [cfe] unspecified
	/\/ ^^^^^^^^^^^^^^
	/\/ [analyzer] unspecified

	}
	}
	""",
	remove: {ErrorSource.cfe},
	errors: [
	makeError(
	line: 6,
	column: 5,
	length: 14,
	cfeError: "Setter not found: 'xx'.",
	),
	makeError(
	line: 16,
	column: 7,
	cfeError: "The method 'call' isn't defined for the class 'int'.",
	),
	],
	expected: """
	int get xx => 3;
	int get yy => 3;

	class A {
	void test() {
	xx = 1;
	/\/ ^^^^^^^^^^^^^^
	/\/ [analyzer] unspecified
	/\/ [cfe] Setter not found: 'xx'.


	yy(4);
	/\/ ^^^^^^^^^^^^^^
	/\/ [analyzer] unspecified
	/\/ ^
	/\/ [cfe] The method 'call' isn't defined for the class 'int'.

	}
	}
	""",
	);
	}

	void expectUpdate(
	String original, {
	List<StaticError>? errors,
	Set<ErrorSource>? remove,
	bool? includeContext,
	String? expected,
	}) {
	errors ??= const [];
	remove ??= ErrorSource.all.toSet();
	includeContext ??= false;

	var actual = updateErrorExpectations(
	'some_test.dart',
	original,
	errors,
	remove: remove,
	includeContext: includeContext,
	);
	if (actual != expected) {
	// Not using Expect.equals() because the diffs it shows aren't helpful for
	// strings this large.
	var actualLines = actual.split("\n");
	var expectedLines = expected!.split("\n");

	// Figure out which leading lines do match so we can ignore those and
	// highlight the offending ones.
	var matchingActual = <int>{};
	var matchingExpected = <int>{};
	for (
	var i = 0;
	i < math.min(actualLines.length, expectedLines.length);
	i++
	) {
	if (actualLines[i] != expectedLines[i]) break;
	matchingActual.add(i);
	matchingExpected.add(i);
	}

	// Find which trailing lines are the same so we can hide those too.
	for (
	var i = 0;
	i < math.min(actualLines.length, expectedLines.length);
	i++
	) {
	// Count backwards from the ends of each list.
	var actualIndex = actualLines.length - i - 1;
	var expectedIndex = expectedLines.length - i - 1;
	if (actualLines[actualIndex] != expectedLines[expectedIndex]) break;
	matchingActual.add(actualIndex);
	matchingExpected.add(expectedIndex);
	}

	var buffer = StringBuffer();
	void writeLine(int index, String line, Set<int> matchingLines) {
	// Only show the line if it was different from the expectation.
	if (matchingLines.contains(index)) {
	buffer.writeln(" : $line");
	} else {
	buffer.writeln("${(index + 1).toString().padLeft(4)}: $line");
	}
	}

	buffer.writeln("Output did not match expectation. Expected:");
	for (var i = 0; i < expectedLines.length; i++) {
	writeLine(i, expectedLines[i], matchingExpected);
	}

	buffer.writeln();
	buffer.writeln("Was:");
	for (var i = 0; i < actualLines.length; i++) {
	writeLine(i, actualLines[i], matchingActual);
	}

	Expect.fail(buffer.toString());
	}
	}