📚 Add test documentation to the readme file (#1734)

Add test documentation to the readme file

tests/README.md

@@ -0,0 +1,154 @@
+# Test Documentation for Anomalib
+
+This guide provides instructions on how to run the tests for Anomalib
+using either `pytest` or `tox`. Running tests is crucial for verifying the
+functionality and stability of the framework.
+
+## Prerequisites
+
+Before running the tests, make sure you have the following prerequisites
+installed:
+
+- Python 3.8 or newer
+- `pre-commit`
+- `pytest`
+- `pytest-cov`
+- `pytest-sugar`
+- `pytest-xdist`
+- `coverage[toml]`
+- `tox`
+
+## Setup
+
+It is recommended to run Python projects in a virtual environment to manage
+dependencies easily.
+
+To create and activate a virtual environment:
+
+```bash
+conda create -n anomalib_env python=3.10
+conda activate anomalib_env
+
+# Or using your favorite virtual environment
+# ...
+
+# Clone the repository and install in editable mode
+git clone https://github.com/openvinotoolkit/anomalib.git
+cd anomalib
+pip install -e .[all]
+```
+
+`.[all]` will install all the dependencies. Alternatively, test pre-requisites
+can be installed via `pip install -e requirements/dev.txt`.
+
+## Running Tests with `pytest`
+
+`pytest` is a powerful testing tool that allows for detailed test execution.
+
+To run all tests with pytest, execute:
+
+```bash
+pytest
+```
+
+Run a specific test file:
+
+```bash
+pytest tests/path/to/test_file.py
+```
+
+For verbose output:
+
+```bash
+pytest -v
+```
+
+### Checking Test Coverage with `pytest-cov
+
+`pytest-cov` is a plugin for pytest that provides coverage reporting. You can
+use it to measure the code coverage of your tests. Here's how to run it:
+
+```bash
+# To run pytest with coverage
+pytest --cov=./
+```
+
+This command will run all tests and report the coverage of your project.
+If you want to generate a coverage report in HTML format, you can use the
+`--cov-report` option:
+
+To generate a coverage report in HTML format
+
+```bash
+pytest --cov=./ --cov-report html
+```
+
+After running this command, you will find a new directory named `htmlcov`. Open
+the `index.html` file in this directory to view the coverage report.
+This will provide instructions on how to check test coverage with `pytest-cov.`
+
+## Running Tests with `tox`
+
+`tox` is a tool that automates testing across multiple Python environments,
+ensuring compatibility. In Anomalib, `tox` is used to automate multiple tests.
+Here's a brief explanation of each:
+
+- `pre-commit`: These tests are run before each commit is made to the
+  repository. They're used to catch issues early and prevent problematic code
+  from being committed to the repository. They can include things like style
+  checks, unit tests, and static analysis.
+
+- `pre-merge`: These tests are run before code is merged into a main or release
+  branch. They are typically more extensive than pre-commit tests and may
+  include integration tests, performance tests, and other checks that are too
+  time-consuming to run on every commit.
+
+- `nightly`: These are tests that are run on a regular schedule, typically once
+  per day ("nightly"). They can include long-running tests, extensive test
+  suites that cover edge cases, or tests that are too resource-intensive to run
+  on every commit or merge.
+
+- `trivy-scan`: Trivy is a comprehensive, open-source vulnerability scanner for
+  containers. A `trivy-scan` would check your project's dependencies for known
+  security vulnerabilities.
+
+- `bandit-scan`: Bandit is a tool designed to find common security issues in
+  Python code. It would check your code for potential security vulnerabilities.
+
+To run these tests, you can use the `tox` command followed by the test
+environment. Here are some examples:
+
+To run the pre-commit tests
+
+```bash
+tox -e pre-commit
+```
+
+To run the pre-merge tests
+
+```bash
+tox -e pre-merge
+```
+
+To run the nightly tests
+
+```bash
+tox -e nightly
+```
+
+To run the trivy-scan
+
+```bash
+tox -e trivy-scan
+```
+
+To run the bandit-scan
+
+```bash
+tox -e bandit-scan
+```
+
+### Checking Test Coverage with `tox`
+
+`tox` in Anomalib is configured to run the pytest coverage. This means that if
+the tests are run via `tox`, the coverage report is automatically generated.