Dark Test Files (testfiles)

Many backend Dark tests are written outside of F# code, so that they may be written more tersely and not require recompilation between executions. This directory houses those testfiles and data used within them.

Refer to docs/unittests.md for instructions on running tests, and READMEs within the subdirectories on how to write types of tests.

Subdirectories

Tests files

• execution files are used to test the Dark language and most of the standard library
• httpclient files are used to test the HTTP Client in the standard library
• http-server files test the HTTP handlers hosted by darklang serve (driven through Stdlib.HttpServer.serve)

Accessory/data

• data houses static assets useful in tests

Syntax (Parser.fs)

All "Dark code" in tests is parsed by the F# parser, then converted from F# to Dark - the conversion is within Parser.fs. The error messages around this are not very good, but there are a few things to be careful of:

• be explicit around pipes, wrapping them in parens to make sure the right expression is being piped. Otherwise you will typically get type errors.

• to produce results that are hard to otherwise create, you can add functions to LibTest.fs. For example, Test.nan_v0 produces a NaN float, and Test.runtimeError produces a built-in error.

When new langauge constructs are added to Dark, updates are often also required in Parser.fs.