Improve test documentation

Change-Id: I505b114f04d3d689010b41c2774243237cfcc8cb
Reviewed-on: https://chromium-review.googlesource.com/c/crossbench/+/3961054
Reviewed-by: Victor Gomes <victorgomes@chromium.org>
diff --git a/README.md b/README.md
index ef85c44..fe6a1c5 100644
--- a/README.md
+++ b/README.md
@@ -30,9 +30,20 @@
 
 ## Run Unit tests
 ```
-poetry run python -m unittest
+poetry run pytest
 ```
 
+Run detailed test coverage:
+```
+poetry run pytest --cov=crossbench --cov-report=html
+```
+
+Run [pytype](https://github.com/google/pytype) type checker:
+```
+poetry run pytype -j auto crossbench
+```
+
+
 ## Main Components
 
 ### Browsers
@@ -45,8 +56,8 @@
 poetry run crossbench speedometer_2.0 \
     --browser=/path/to/chromium  \
     -- \
-    --browser-flag-foo \
-    --browser-flag-bar \
+        --browser-flag-foo \
+        --browser-flag-bar \
 ```
 
 For more complex scenarios you can use a