Document test strategy

testing.md

@@ -0,0 +1,172 @@
+# Test strategy
+
+## Exploratory tests
+
+These tests are intended to verify that the extension subjectively behaves as
+expected without disrupting normal functionality of the site.
+
+It is recommended to perform these tests with "Show thumbnail hashes" enabled
+in the extension settings, as this helps to verify that the extension is
+working even when there are no duplicates on the page.
+
+1. Front page
+
+    1. Navigate to https://old.reddit.com/.
+
+    2. Verify that the page functions as usual.
+
+    3. Open the console, filter to rededup.js and verify that there are no
+       errors. There should be two log messages: "Processing X links" and "No
+       duplicates found" or "Found Y items with Z total duplicates".
+
+    4. If there are any duplicates (unlikely for the front page), verify that
+       the duplicate show/hide behavior works as expected.
+
+2. Subreddit
+
+    1. Navigate to a subreddit page.
+
+    2. Repeat the steps for the front page.
+
+3. User page
+
+    1. Find a user with duplicate posts (look on art-related subs like /r/IDAP
+       or /r/Illustration).
+
+    2. Verify that duplicates are handled as expected on the user's overview
+       page and submissions page.
+
+    3. Verify that the user comments page work as usual (log message "No links
+       found").
+
+4. Post comments
+
+    1. Find a link that has been posted more than once (look on /r/news or
+       similar).
+
+    2. Navigate to the post comments and verify the page works as usual.
+       (The extension will log "Processing 1 link", "No duplicates found".)
+
+    3. Click on the "Other Discussions" tab and verify that the page works as
+       usual. The extension should log "Other Discussions page" and not process
+       any links.
+
+## Functionality
+
+These tests use specific posts to verify the deduplication functionality.
+
+1. Deduplicate by thumbnail
+
+    1. Navigate to https://old.reddit.com/by_id/t3_jrjed7,t3_jrqhj4,t3_jo1qwh,t3_jri2y8.
+
+    2. Verify that posts are collated as expected.
+
+        * Post order should be jrjed7, jrqhj4, jri2y8, jo1qwh.
+        * jrjed7 should have "(2 duplicates — show)" at end of tagline.
+        * jrqhj4 and jri2y8 should be hidden (inline style "display: none").
+        * jo1qwh should not be modified.
+
+    3. Verify that show/hide link works as expected.
+        * Clicking "show" link should reveal jrqhj4 and jri2y8 and update
+          tagline to "hide".
+        * Clicking "hide" link should hide jrqhj4 and jri2y8 and update tagline
+          to "show".
+
+2. Deduplicate by URL
+
+    1. Navigate to https://old.reddit.com/by_id/t3_jyu5b2,t3_jysgvx,t3_jyu73g.
+
+    2. Verify that posts are collated as expected.
+
+        * Post order should be jyu5b2, jyu73g, jysgvx.
+        * jyu5b2 should have "(1 duplicate — show)" at end of tagline.
+        * jyu73g should be hidden.
+
+    3. Verify that show/hide link works as expected.
+
+4. Deduplicate by URL (crosspost)
+
+    1. Navigate to https://old.reddit.com/by_id/t3_jyu5b2,t3_jyvuiz.
+
+    2. Verify that posts are collated as expected.
+
+        * Post order should be jyu5b2, jyvuiz.
+        * jyu5b2 should have "(1 duplicate — show)" at end of tagline.
+        * jyvuiz should be hidden.
+
+    3. Verify that show/hide link works as expected.
+
+4. Deduplicate multiple
+
+    1. Navigate to https://old.reddit.com/by_id/t3_jrjed7,t3_jysgvx,t3_jyu5b2,t3_jrqhj4,t3_jo1qwh,t3_jyu73g,t3_jri2y8,t3_jyvuiz.
+
+    2. Verify that posts are collated as expected.
+
+        * Post order should be jrjed7, jrqhj4, jri2y8, jysgvx, jyu5b2, jyu73g,
+          jyvuiz, jo1qwh.
+        * jrjed7 should have "(2 duplicates — show)" at end of tagline.
+        * jrqhj4 and jri2y8 should be hidden.
+        * jyu5b2 should have "(2 duplicates — show)" at end of tagline.
+        * jyu73g and jyvuiz should be hidden.
+
+    3. Verify that both show/hide links work as expected.
+
+## Settings
+
+These tests verify the settings UI and the different settings values.
+
+1. Deduplicate by
+
+    1. Navigate to https://old.reddit.com/by_id/t3_jrjed7,t3_jrqhj4
+
+    2. Verify that the two posts are collated.
+
+    3. In the extension settings, select "URL only" deduplication mode.
+
+    4. Refresh the page from step 1.
+
+    5. Verify that the two posts are not collated.
+
+2. Hash function
+
+    1. Navigate to https://old.reddit.com/by_id/t3_jz43h4,t3_jz3x31.
+
+    2. Verify that the two posts are collated.
+
+    3. In the extension settings, select the "Difference Hash" function.
+
+    4. Refresh the page from step 1.
+
+    5. Verify that the two posts are still collated.
+
+3. Hamming distance
+
+    1. Navigate to https://old.reddit.com/by_id/t3_it6czg,t3_it6el1,t3_it8ric.
+
+    2. Verify that all three posts are collated.
+
+    3. In the extension settings, set the Hamming Distance to 0 (exact match).
+
+    4. Refresh the page from step 1.
+
+    5. Verify that only it6czg and it6el1 are collated.
+
+4. Partition by domain
+
+    1. Navigate to https://old.reddit.com/by_id/t3_jyymza,t3_jyyy2a.
+
+    2. Verify that the two posts are not collated.
+
+    3. In the extension settings, disable "Partition by domain".
+
+    4. Refresh the page from step 1.
+
+    5. Verify that the posts are collated.
+
+5. Show hash values
+
+    1. In the extension settings, enable "Show hash values".
+
+    2. On https://old.reddit.com/, verify that posts with a thumbnail have an
+       image hash value in the tagline. The hash string should be 16 hex
+       digits.