Pull out a base class from DumpAccessibilityTree

content/browser/accessibility/dump_accessibility_browsertest_base.h

+// Copyright (c) 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <string>
+#include <vector>
+
+#include "base/strings/string16.h"
+#include "content/browser/accessibility/accessibility_tree_formatter.h"
+#include "content/public/test/content_browser_test.h"
+
+namespace content {
+
+// Base class for an accessibility browsertest that takes an HTML file as
+// input, loads it into a tab, dumps some accessibility data in text format,
+// then compares that text to an expectation file in the same directory.
+//
+// The system was inspired by WebKit/Blink LayoutTests, but customized for
+// testing accessibility in Chromium.
+class DumpAccessibilityTestBase : public ContentBrowserTest {
+ public:
+  // Given a path to an HTML file relative to the test directory,
+  // loads the HTML, loads the accessibility tree, calls Dump(), then
+  // compares the output to the expected result and has the test succeed
+  // or fail based on the diff.
+  void RunTest(const base::FilePath::CharType* file_path);
+
+ protected:
+  //
+  // For subclasses to override:
+  //
+
+  // This is called by RunTest after the document has finished loading,
+  // including the load complete accessibility event. The subclass should

[David Tseng, 2014/12/17 01:03:32]

Now that we test events, would we ever want to start event logging ebfore load
complete?

[dmazzoni, 2014/12/17 07:04:51]

Sure - not a super high priority for me right now but we could consider that
later.

+  // dump whatever that specific test wants to dump, returning the result
+  // as a sequence of strings.
+  virtual std::vector<std::string> Dump() = 0;
+
+  // Add the default filters that are applied to all tests. Each subclass
+  // should override this.

[David Tseng, 2014/12/17 01:03:32]

Since this method is pure virtual, this comment is unnecessary.

[dmazzoni, 2014/12/17 07:04:50]

Done.

+  virtual void AddDefaultFilters(
+      std::vector<AccessibilityTreeFormatter::Filter>* filters) = 0;
+
+  // This gets called if the diff didn't match; the test can print
+  // additional useful info.
+  virtual void AdditionalErrorLogging() {}

[David Tseng, 2014/12/17 01:03:32]

Name of this method should reflect the comment more; maybe OnDiffFailed?

[dmazzoni, 2014/12/17 07:04:51]

Done.

+
+  //
+  // Helpers
+  //
+
+  // Dump the whole accessibility tree, without applying any filters,
+  // and return it as a string.
+  base::string16 DumpUnfilteredAccessibilityTreeAsString();
+
+  // Utility helper that does a comment-aware equality check.
+  // Returns array of lines from expected file which are different.
+  std::vector<int> DiffLines(const std::vector<std::string>& expected_lines,
+                             const std::vector<std::string>& actual_lines);
+
+  // Parse the test html file and parse special directives, usually
+  // beginning with an '@' and inside an HTML comment, that control how the
+  // test is run and how the results are interpreted.
+  //
+  // When the accessibility tree is dumped as text, each attribute is
+  // run through filters before being appended to the string. An "allow"
+  // filter specifies attribute strings that should be dumped, and a "deny"
+  // filter specifies strings that should be suppressed. As an example,
+  // @MAC-ALLOW:AXSubrole=* means that the AXSubrole attribute should be
+  // printed, while @MAC-ALLOW:AXSubrole=AXList* means that any subrole
+  // beginning with the text "AXList" should be printed.
+  //
+  // The @WAIT-FOR:text directive allows the test to specify that the document
+  // may dynamically change after initial load, and the test is to wait
+  // until the given string (e.g., "text") appears in the resulting dump.
+  // A test can make some changes to the document, then append a magic string
+  // indicating that the test is done, and this framework will wait for that
+  // string to appear before comparing the results.
+  void ParseHtmlForExtraDirectives(
+      const std::string& test_html,
+      std::vector<AccessibilityTreeFormatter::Filter>* filters,
+      std::string* wait_for);
+
+  // The default filters plus the filters loaded from the test file.
+  std::vector<AccessibilityTreeFormatter::Filter> filters_;
+};
+
+}  // namespace content