Tests added.

Some bug solved.

README.md

@@ -1,5 +1,49 @@
 # pyapp-engine
 
+# Development
+
+## Installation
+
+```bash
+pip install -e ".[dev,docs]"
+```
+
+## Running the tests
+
+```bash
+pytest
+```
+
+Coverage report is displayed automatically in the terminal. Other formats:
+
+```bash
+pytest --cov-report=html    # htmlcov/index.html  (browsable)
+pytest --cov-report=xml     # coverage.xml        (CI tools)
+pytest --cov-report=term    # terminal summary only
+```
+
+Reports can be combined:
+
+```bash
+pytest --cov-report=term-missing --cov-report=html
+```
+
+## Documentation
+
+Preview locally:
+
+```bash
+mkdocs serve
+# available at http://127.0.0.1:8000
+```
+
+Build the static site:
+
+```bash
+mkdocs build
+# output in site/
+```
+
 # License
 
 The pyapp-engine module was written by François Dausseur fdausseur@free.fr.