Port dart:io Path tests to package:path.

pkg/path/test/relative_test.dart

+// Copyright (c) 2013, 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.
+//
+// Test "relative" on all styles of path.Builder, on all platforms.
+
+import "package:unittest/unittest.dart";
+import "package:path/path.dart" as path;
+
+void main() {
+  test("test relative", () {
+    relativeTest(new path.Builder(style: path.Style.posix, root: '.'), '/');
+    relativeTest(new path.Builder(style: path.Style.posix, root: '/'), '/');
+    relativeTest(new path.Builder(style: path.Style.windows, root: r'd:\'),
+                 r'c:\');
+    relativeTest(new path.Builder(style: path.Style.windows, root: '.'),
+                 r'c:\');
+    relativeTest(new path.Builder(style: path.Style.url, root: 'file:///'),
+                 'http://myserver/');
+    relativeTest(new path.Builder(style: path.Style.url, root: '.'),
+                 'http://myserver/');
+    relativeTest(new path.Builder(style: path.Style.url, root: 'file:///'),
+                 '/');
+    relativeTest(new path.Builder(style: path.Style.url, root: '.'), '/');
+  });
+}
+
+void relativeTest(path.Builder builder, String prefix) {
+  var isRelative = (builder.root == '.');
+  // Cases where the arguments are absolute paths.
+  expectRelative(result, pathArg, fromArg) {
+    expect(builder.normalize(result), builder.relative(pathArg, from: fromArg));
+  }
+
+  expectRelative('c/d', '${prefix}a/b/c/d', '${prefix}a/b');
+  expectRelative('c/d', '${prefix}a/b/c/d', '${prefix}a/b/');
+  expectRelative('.', '${prefix}a', '${prefix}a');
+  // Trailing slashes in the inputs have no effect.
+  expectRelative('../../z/x/y', '${prefix}a/b/z/x/y', '${prefix}a/b/c/d/');
+  expectRelative('../../z/x/y', '${prefix}a/b/z/x/y', '${prefix}a/b/c/d');
+  expectRelative('../../z/x/y', '${prefix}a/b/z/x/y/', '${prefix}a/b/c/d');
+  expectRelative('../../../z/x/y', '${prefix}z/x/y', '${prefix}a/b/c');
+  expectRelative('../../../z/x/y', '${prefix}z/x/y', '${prefix}a/b/c/');
+
+  // Cases where the arguments are relative paths.
+  expectRelative('c/d', 'a/b/c/d', 'a/b');
+  expectRelative('.', 'a/b/c', 'a/b/c');
+  expectRelative('.', 'a/d/../b/c', 'a/b/c/');
+  expectRelative('.', '', '');
+  expectRelative('.', '.', '');
+  expectRelative('.', '', '.');
+  expectRelative('.', '.', '.');
+  expectRelative('.', '..', '..');
+  if (isRelative) expectRelative('..', '..', '.');
+  expectRelative('a', 'a', '');
+  expectRelative('a', 'a', '.');
+  expectRelative('..', '.', 'a');
+  expectRelative('.', 'a/b/f/../c', 'a/e/../b/c');
+  expectRelative('d', 'a/b/f/../c/d', 'a/e/../b/c');
+  expectRelative('..', 'a/b/f/../c', 'a/e/../b/c/e/');
+  expectRelative('../..', '', 'a/b/');
+  if (isRelative) expectRelative('../../..', '..', 'a/b/');
+  expectRelative('../b/c/d', 'b/c/d/', 'a/');
+  expectRelative('../a/b/c', 'x/y/a//b/./f/../c', 'x//y/z');
+
+  // Case where from is an exact substring of path.
+  expectRelative('a/b', '${prefix}x/y//a/b', '${prefix}x/y/');
+  expectRelative('a/b', 'x/y//a/b', 'x/y/');
+  expectRelative('../ya/b', '${prefix}x/ya/b', '${prefix}x/y');
+  expectRelative('../ya/b', 'x/ya/b', 'x/y');
+  expectRelative('../b', 'x/y/../b', 'x/y/.');
+  expectRelative('a/b/c', 'x/y/a//b/./f/../c', 'x/y');
+  expectRelative('.', '${prefix}x/y//', '${prefix}x/y/');
+  expectRelative('.', '${prefix}x/y/', '${prefix}x/y');
+
+  // Should always throw - no relative path can be constructed.
+  if (isRelative) {
+    expect(() => builder.relative('.', from: '..'), throwsArgumentError);
+    expect(() => builder.relative('a/b', from: '../../d'),
+           throwsArgumentError);
+    expect(() => builder.relative('a/b', from: '${prefix}a/b'),
+           throwsArgumentError);
+    // An absolute path relative from a relative path returns the absolute path.
+    expectRelative('${prefix}a/b', '${prefix}a/b', 'c/d');
+  }
+}