Parsing config files

The rtf-config crate provides parsers for the three config files used by RTF, along with parsers for the various provider fragments that are used to expose the rest of the framework to users through those config files.

The parsers for TestPlanConfig, EnvironmentConfig and ScenarioConfig live in the formats module. Each exposes a similar API for how they are parsed from YAML data files, templated, validated and executed. The shared behaviour used to do this is defined in a set of traits that provide tree-walk based methods for traversing the nested data structures obtained from parsing user written config files.

Config resolution & execution

The full resolution and execution of a test plan has the following flow:

1. Load and parse the user specified TestPlan file.
2. Locate and load any required Scenario and Environment files defined in from directives as raw YAML. If the test plan defines overrides for either section then deep merge before parsing into concrete structs.
3. Check that the test plan contains all of the required variables for templating to be possible. If it doesn’t then early exit reporting the missing variables.
4. Template the environment setup section before running static analysis checks.
5. If all checks pass, run the setup command and use the provided output to finish templating the scenario and environment teardown sections.
6. Run static analysis checks for both sections. If any checks fail for either section then early exit.
7. Run the test scenario.
8. Run the environment teardown.

For each of these stages we check for any errors or inconsistencies and report all known errors to the user as a batch operation. Each of the config file structs provides an API for running partial checks and templating so that end users are able to efficiently debug and iterate on their config files.