なんでもIDをつけましょう。そうすれば、コードの詳細を知らなくても、問題箇所が機械的に特定できます。

6. $ python tests/api_books_test.py
* GET /api/2/books
- [pass] returns list of books.
- [Fail] accepts 'size' parameter.
---------------------------------------------
[Fail] API_Test > GET /api/2/books
> 002: accepts 'size' parameter.
File "tests/api_books_test.py", line 268
ok (len(items)) == 20
AssertionError: 33 == 20 : failed.
---------------------------------------------

7. class BooksAPI_Test(TestCase):
with subject("/api/v1/books"):
@test("accepts 'size' parameter.")
def _(self, api):
qs = "size=20"
resp = api.GET('/api/v1/books?'+qs)
books = resp.json['books']
ok (len(books)) == 20

8. $ ls app/**/*.py | wc -l
123
$ ls app/api/**.py | wc -l
23
$ ls app/models/**.py | wc -l
45
$ ls app/usecases/**.py | wc -l
55

9. GET /api/v1/books
class BooksAPI
def do_list()
class BooksService
def find_books()

10. class BookService(Service):
def find_books(self, **kwargs):
q = db.query(Book)
order = kwargs.pop('order')
if order: q = q.order_by(order)
limit = kwargs.pop('limit')
if limit: q = q.limit(limit)
if kwargs: q = q.filter_by(**kwargs)
return q.all()

12. class BookService(Service):
def find_books(self, **kwargs):
q = db.query(Book)
order = kwargs.pop('order')
if order: q = q.order_by(order)
#; [!mf7cw] accepts 'size' parameter.
limit = kwargs.pop('limit')
if limit: q = q.limit(limit)
if kwargs: q = q.filter_by(**kwargs)
return q.all()

13. class BooksAPI_Test(TestCase):
with subject("/api/v1/books"):
@test("[!mf7cw] accepts 'size' parameter.")
def _(self, api):
qs = "size=20"
resp = api.GET('/api/v1/books?'+qs)
books = resp.json['books']
ok (len(books)) == 20

14. $ python tests/api_books_test.py
* GET /api/2/books
- [pass] returns list of books.
- [Fail] accepts 'size' parameter.
---------------------------------------------
[Fail] API_Test > GET /api/2/books
> 002: [!mf7cw] accepts 'size' parameter.
File "tests/api_books_test.py", line 268
ok (len(items)) == 20
AssertionError: 33 == 20 : failed.
---------------------------------------------

15. ## -n: -r:
$ grep -nr mf7cw app
app/services/book_service.py:199: #; [!mf7cw]
accepts 'size' parameter.

16. ## file: app/services/book_service.py
194: class BookService(Service):
195: def find_books(self, **kwargs):
196: q = db.query(Book)
197: order = kwargs.pop('order')
198: if order: q = q.order_by(order)
199: #; [!mf7cw] accepts 'size' parameter.
200: limit = kwargs.pop('limit')
201: if limit: q = q.limit(limit)
202: if kwargs: q = q.filter_by(**kwargs)
203: return q.all()

20. $ less /var/log/postgresql/pg9.3-main.log
2016-12-01 12:34:56 JST [46212]
LOG: duration: 2671.751 ms
statement:
select * from books
where title like '%SQL%'
order by title
limit 100
.....

21. $ ls app/**/*.py | wc -l
123
$ ls app/api/**.py | wc -l
23
$ ls app/models/**.py | wc -l
45
$ ls app/usecases/**.py | wc -l
55

23. sql = """
/* [sql:dolxq] */
select *
from books
where title like :pattern
order by title
limit :limit
"""
vars = {"title": "%SQL%", limit: 10}
result = db.execute(sql, vars)

24. 2016-12-01 12:34:56 JST [46212]
LOG: duration: 2671.751 ms
statement:
/* [sql:dolxq] */
select * from books
where title like '%SQL%'
order by title
limit 100

25. ## grep ag (SilverSearcher)
$ ag dolxq app
app/services/book_service.py
79: /* [sql:dolxq] */

26. ## file: app/services/book_service.py
78: sql = """
79: /* [sql:dolxq] */
80: select *
81: from books
82: where title like :pattern
83: order by title
84: limit :limit
85: """
86: vars = {"title": "%SQL%", limit: 10}
87: result = db.execute(sql, vars)

30. <p>
<form>
Name: <input name="name">
Comment: <input name="comment">
<input type="submit">
</form>
</p>

31. $ ls app/**/*.html* | wc -l
302
$ ls app/**/*.py | wc -l
123

33. <!-- [!v5ozp] -->
<p>
<form>
Name: <input name="name">
Comment: <input name="comment">
<input type="submit">
</form>
</p>

34. <p data-eid="!v5ozp">
<form>
Name: <input name="name">
Comment: <input name="comment">
<input type="submit">
</form>
</p>

35. <!-- [!v5ozp] -->
<p>
<form>
Name: <input name="name">
Comment: <input name="comment">
<input type="submit">
</form>
</p>

36. ## rak (ruby) ack (perl)
$ rak v5ozp app
app/templates/example_form.html.tjn
25| <!-- [!v5ozp] -->

37. ## file: example_form.html.tjn
24:
25: <!-- [!v5ozp] -->
26: <p>
27: <form>
28: Name: <input name="name">
29: Comment: <input name="comment">
30: <input type="submit">
31: </form>
32: </p>

39. function render() {
return (
<div data-eid="!1tscw">
<h3>TODO</h3>
<TodoList items={this.state.items} />
<form onSubmit={this.handleSubmit}>
<input value={this.state.text} />
<button>Add</button>
</form>
</div>
);
}