Auto merge of #270 - micbou:refactor-tests, r=Valloric

[READY] Refactoring integration tests

### Changes
- Move related completer tests to their own subdirectories:
```
ycmd
  └── tests
      ├── clang
      │   ├── testdata
      │   ├── __init__.py
      │   ├── get_completions_test.py
      │   ├── diagnostics_test.py
      │   ├── subcommands_test.py
      │   └── utils.py
      ├── cs ── ...
      ├── python ── ...
      ├── go ── ...
      ...
```
- Regroup tests in classes and subclasses: take advantage of fixtures (`setUp` and `tearDown` methods) and inheritance.
- Rename tests: names are now shorter;
- Fix coding style;
- Update copyright notices;
- No tests were harmed during the making of this PR: 458 tests before, 458 tests after.

### Issues?
- Code to set the Bottle debug mode:
```python
import bottle

bottle.debug( True )
```
was removed from all tests inheriting from `Handlers_test` where it is set in the `setUp` method. Is it enough to enable debug mode in all tests? I don't know how to check this.
- `Basic_test` and `ZeroBasedLineAndColumn_test` tests in `Cs_Diagnostics_test` are near to be identical. Should we remove one of them?

<!-- Reviewable:start -->
[<img src="https://reviewable.io/review_button.png" height=40 alt="Review on Reviewable"/>](https://reviewable.io/reviews/valloric/ycmd/270)
<!-- Reviewable:end -->

test_requirements.txt

@@ -4,4 +4,3 @@ nose>=1.3.0
 PyHamcrest>=1.8.0
 WebTest>=2.0.9
 ordereddict>=1.1
-contextlib2>=0.4.0

ycmd/tests/clang/clang_handlers_test.py

@@ -0,0 +1,26 @@
+#!/usr/bin/env python
+#
+# Copyright (C) 2015 ycmd contributors.
+#
+# This file is part of ycmd.
+#
+# ycmd is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# ycmd is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with ycmd.  If not, see <http://www.gnu.org/licenses/>.
+
+from ..handlers_test import Handlers_test
+
+
+class Clang_Handlers_test( Handlers_test ):
+
+  def __init__( self ):
+    self._file = __file__

ycmd/tests/clang/diagnostics_test.py

@@ -0,0 +1,212 @@
+#!/usr/bin/env python
+#
+# Copyright (C) 2015 ycmd contributors.
+#
+# This file is part of ycmd.
+#
+# ycmd is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# ycmd is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with ycmd.  If not, see <http://www.gnu.org/licenses/>.
+
+from ...server_utils import SetUpPythonPath
+SetUpPythonPath()
+from hamcrest import ( assert_that, contains, contains_string, has_entries,
+                       has_entry, has_items, empty, equal_to )
+from clang_handlers_test import Clang_Handlers_test
+from pprint import pprint
+
+
+class Clang_Diagnostics_test( Clang_Handlers_test ):
+
+  def ZeroBasedLineAndColumn_test( self ):
+    contents = """
+void foo() {
+  double baz = "foo";
+}
+// Padding to 5 lines
+// Padding to 5 lines
+"""
+
+    event_data = self._BuildRequest( compilation_flags = ['-x', 'c++'],
+                                     event_name = 'FileReadyToParse',
+                                     contents = contents,
+                                     filetype = 'cpp' )
+
+    results = self._app.post_json( '/event_notification', event_data ).json
+    assert_that( results,
+                 contains(
+                    has_entries( {
+                      'kind': equal_to( 'ERROR' ),
+                      'text': contains_string( 'cannot initialize' ),
+                      'ranges': contains( has_entries( {
+                        'start': has_entries( {
+                          'line_num': 3,
+                          'column_num': 16,
+                        } ),
+                        'end': has_entries( {
+                          'line_num': 3,
+                          'column_num': 21,
+                        } ),
+                      } ) ),
+                      'location': has_entries( {
+                        'line_num': 3,
+                        'column_num': 10
+                      } ),
+                      'location_extent': has_entries( {
+                        'start': has_entries( {
+                          'line_num': 3,
+                          'column_num': 10,
+                        } ),
+                        'end': has_entries( {
+                          'line_num': 3,
+                          'column_num': 13,
+                        } ),
+                      } )
+                    } ) ) )
+
+
+  def SimpleLocationExtent_test( self ):
+    contents = """
+void foo() {
+  baz = 5;
+}
+// Padding to 5 lines
+// Padding to 5 lines
+"""
+
+    event_data = self._BuildRequest( compilation_flags = ['-x', 'c++'],
+                                     event_name = 'FileReadyToParse',
+                                     contents = contents,
+                                     filetype = 'cpp' )
+
+    results = self._app.post_json( '/event_notification', event_data ).json
+    assert_that( results,
+                 contains(
+                    has_entries( {
+                      'location_extent': has_entries( {
+                        'start': has_entries( {
+                          'line_num': 3,
+                          'column_num': 3,
+                        } ),
+                        'end': has_entries( {
+                          'line_num': 3,
+                          'column_num': 6,
+                        } ),
+                      } )
+                    } ) ) )
+
+
+  def PragmaOnceWarningIgnored_test( self ):
+    contents = """
+#pragma once
+
+struct Foo {
+  int x;
+  int y;
+  int c;
+  int d;
+};
+"""
+
+    event_data = self._BuildRequest( compilation_flags = ['-x', 'c++'],
+                                     event_name = 'FileReadyToParse',
+                                     contents = contents,
+                                     filepath = '/foo.h',
+                                     filetype = 'cpp' )
+
+    response = self._app.post_json( '/event_notification', event_data ).json
+    assert_that( response, empty() )
+
+
+  def Works_test( self ):
+    contents = """
+struct Foo {
+  int x  // semicolon missing here!
+  int y;
+  int c;
+  int d;
+};
+"""
+
+    diag_data = self._BuildRequest( compilation_flags = ['-x', 'c++'],
+                                    line_num = 3,
+                                    contents = contents,
+                                    filetype = 'cpp' )
+
+    event_data = diag_data.copy()
+    event_data.update( {
+      'event_name': 'FileReadyToParse',
+    } )
+
+    self._app.post_json( '/event_notification', event_data )
+    results = self._app.post_json( '/detailed_diagnostic', diag_data ).json
+    assert_that( results,
+                 has_entry( 'message', contains_string( "expected ';'" ) ) )
+
+
+  def Multiline_test( self ):
+    contents = """
+struct Foo {
+  Foo(int z) {}
+};
+
+int main() {
+  Foo foo("goo");
+}
+"""
+
+    diag_data = self._BuildRequest( compilation_flags = [ '-x', 'c++' ],
+                                    line_num = 7,
+                                    contents = contents,
+                                    filetype = 'cpp' )
+
+    event_data = diag_data.copy()
+    event_data.update( {
+      'event_name': 'FileReadyToParse',
+    } )
+
+    self._app.post_json( '/event_notification', event_data )
+    results = self._app.post_json( '/detailed_diagnostic', diag_data ).json
+    assert_that( results,
+                 has_entry( 'message', contains_string( "\n" ) ) )
+
+
+  def FixIt_Available_test( self ):
+    contents = open( self._PathToTestFile( 'FixIt_Clang_cpp11.cpp' ) ).read()
+
+    event_data = self._BuildRequest( contents = contents,
+                                     event_name = 'FileReadyToParse',
+                                     filetype = 'cpp',
+                                     compilation_flags = [ '-x', 'c++',
+                                                           '-std=c++03',
+                                                           '-Wall',
+                                                           '-Wextra',
+                                                           '-pedantic' ] )
+
+    response = self._app.post_json( '/event_notification', event_data ).json
+
+    pprint( response )
+
+    assert_that( response, has_items(
+      has_entries( {
+        'location': has_entries( { 'line_num': 16, 'column_num': 3 } ),
+        'text': equal_to( 'switch condition type \'A\' '
+                          'requires explicit conversion to \'int\''),
+        'fixit_available': True
+      } ),
+      has_entries( {
+        'location': has_entries( { 'line_num': 11, 'column_num': 3 } ),
+        'text': equal_to(
+           'explicit conversion functions are a C++11 extension' ),
+        'fixit_available': False
+      } ),
+    ) )