added depth spider middleware test

scrapy/tests/test_spidermiddleware_depth.py

+from unittest import TestCase
+
+from scrapy.contrib.spidermiddleware.depth import DepthMiddleware 
+from scrapy.conf import settings
+from scrapy.http import Response, Request
+from scrapy.spider import BaseSpider
+from scrapy.stats import stats
+
+
+class TestDepthMiddleware(TestCase):
+
+    def setUp(self):
+        settings.disabled = False
+        settings.overrides['DEPTH_LIMIT'] = 1
+        settings.overrides['DEPTH_STATS'] = True
+
+        self.spider = BaseSpider()
+        self.spider.domain_name = 'scrapytest.org'
+
+        stats.open_domain(self.spider.domain_name)
+
+        self.mw = DepthMiddleware()
+        self.assertEquals(stats.get_value('envinfo/request_depth_limit'), 1)
+
+    def test_process_spider_output(self):
+        req = Request('http://scrapytest.org')
+        resp = Response('http://scrapytest.org')
+        resp.request = req
+        result = [Request('http://scrapytest.org')]
+
+        out = list(self.mw.process_spider_output(resp, result, self.spider))
+        self.assertEquals(out, result)
+
+        rdc = stats.get_value('request_depth_count/1',
+                              domain=self.spider.domain_name)
+        self.assertEquals(rdc, 1)
+
+        req.meta['depth'] = 1
+
+        out2 = list(self.mw.process_spider_output(resp, result, self.spider))
+        self.assertEquals(out2, [])
+
+        rdm = stats.get_value('request_depth_max',
+                              domain=self.spider.domain_name)
+        self.assertEquals(rdm, 1)
+ 
+    def tearDown(self):
+        del settings.overrides['DEPTH_LIMIT']
+        del settings.overrides['DEPTH_STATS']
+        settings.disabled = True
+
+        stats.close_domain(self.spider.domain_name, '')
+