content/browser/accessibility/dump_accessibility_browsertest_base.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include <string>
   6 #include <vector>
   7
   8 #include "base/strings/string16.h"
   9 #include "content/browser/accessibility/accessibility_tree_formatter.h"
  10 #include "content/public/test/content_browser_test.h"
  11
  12 namespace content {
  13
  14 // Base class for an accessibility browsertest that takes an HTML file as
  15 // input, loads it into a tab, dumps some accessibility data in text format,
  16 // then compares that text to an expectation file in the same directory.
  17 //
  18 // The system was inspired by WebKit/Blink LayoutTests, but customized for
  19 // testing accessibility in Chromium.
  20 class DumpAccessibilityTestBase : public ContentBrowserTest {
  21  public:
  22   DumpAccessibilityTestBase();
  23   ~DumpAccessibilityTestBase() override;
  24
  25   // Given a path to an HTML file relative to the test directory,
  26   // loads the HTML, loads the accessibility tree, calls Dump(), then
  27   // compares the output to the expected result and has the test succeed
  28   // or fail based on the diff.
  29   void RunTest(const base::FilePath file_path, const char* file_dir);
  30
  31  protected:
  32   //
  33   // For subclasses to override:
  34   //
  35
  36   // This is called by RunTest after the document has finished loading,
  37   // including the load complete accessibility event. The subclass should
  38   // dump whatever that specific test wants to dump, returning the result
  39   // as a sequence of strings.
  40   virtual std::vector<std::string> Dump() = 0;
  41
  42   // Add the default filters that are applied to all tests.
  43   virtual void AddDefaultFilters(
  44       std::vector<AccessibilityTreeFormatter::Filter>* filters) = 0;
  45
  46   // This gets called if the diff didn't match; the test can print
  47   // additional useful info.
  48   virtual void OnDiffFailed() {}
  49
  50   //
  51   // Helpers
  52   //
  53
  54   // Dump the whole accessibility tree, without applying any filters,
  55   // and return it as a string.
  56   base::string16 DumpUnfilteredAccessibilityTreeAsString();
  57
  58   // Utility helper that does a comment-aware equality check.
  59   // Returns array of lines from expected file which are different.
  60   std::vector<int> DiffLines(const std::vector<std::string>& expected_lines,
  61                              const std::vector<std::string>& actual_lines);
  62
  63   // Parse the test html file and parse special directives, usually
  64   // beginning with an '@' and inside an HTML comment, that control how the
  65   // test is run and how the results are interpreted.
  66   //
  67   // When the accessibility tree is dumped as text, each attribute is
  68   // run through filters before being appended to the string. An "allow"
  69   // filter specifies attribute strings that should be dumped, and a "deny"
  70   // filter specifies strings that should be suppressed. As an example,
  71   // @MAC-ALLOW:AXSubrole=* means that the AXSubrole attribute should be
  72   // printed, while @MAC-ALLOW:AXSubrole=AXList* means that any subrole
  73   // beginning with the text "AXList" should be printed.
  74   //
  75   // The @WAIT-FOR:text directive allows the test to specify that the document
  76   // may dynamically change after initial load, and the test is to wait
  77   // until the given string (e.g., "text") appears in the resulting dump.
  78   // A test can make some changes to the document, then append a magic string
  79   // indicating that the test is done, and this framework will wait for that
  80   // string to appear before comparing the results.
  81   void ParseHtmlForExtraDirectives(
  82       const std::string& test_html,
  83       std::vector<AccessibilityTreeFormatter::Filter>* filters,
  84       std::string* wait_for);
  85
  86   // The default filters plus the filters loaded from the test file.
  87   std::vector<AccessibilityTreeFormatter::Filter> filters_;
  88 };
  89
  90 }  // namespace content