From 2fd3228525858f594361eba345ff31087f8a917a Mon Sep 17 00:00:00 2001
From: Aleksey Kladov <aleksey.kladov@gmail.com>
Date: Sat, 3 Feb 2018 22:39:01 +0300
Subject: [PATCH] Document inline tests infra

---
 docs/TESTS.md | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/docs/TESTS.md b/docs/TESTS.md
index 8005ec9da6..db06dbebc9 100644
--- a/docs/TESTS.md
+++ b/docs/TESTS.md
@@ -19,12 +19,26 @@ files to have the same name except for the leading number. In general,
 test suite should be append-only: old tests should not be modified,
 new tests should be created instead.
 
-
 Note that only `ok` tests are normative: `err` tests test error
 recovery and it is totally ok for a parser to not implement any error
 recovery at all. However, for libsyntax2.0 we do care about error
 recovery, and we do care about precise and useful error messages.
 
+There are also so-called "inline tests". They appear as the comments 
+with a `test` header in the source code, like this:
+
+```rust
+// test fn_basic
+// fn foo() {}
+fn fn_item(p: &mut Parser) {
+    // ...
+}
+``` 
+
+You can run `cargo collect-tests` command to collect all inline tests 
+into `tests/data/inline` directory. The main advantage of inline tests
+is that they help to illustrate what the relevant code is doing. 
+
 
 Contribution opportunity: design and implement testing infrastructure
 for validators.