Rename integration testing -> ecosystem testing

Author: jieyouxu

src/SUMMARY.md

@@ -25,7 +25,7 @@
     - [Compiletest](./tests/compiletest.md)
         - [UI tests](./tests/ui.md)
         - [Test headers](./tests/headers.md)
-    - [Integration testing](./tests/integration.md)
+    - [Ecosystem testing](./tests/ecosystem.md)
         - [Crater](./tests/crater.md)
         - [Fuchsia](./tests/fuchsia.md)
         - [Rust for Linux](./tests/rust-for-linux.md)

src/tests/ecosystem.md

@@ -0,0 +1,28 @@
+# Ecosystem testing
+
+Rust tests integration with real-world code in the ecosystem to catch
+regressions and make informed decisions about the evolution of the language.
+
+## Testing methods
+
+### Crater
+
+Crater is a tool which runs tests on many thousands of public projects. This
+tool has its own separate infrastructure for running, and is not run as part of
+CI. See the [Crater chapter](crater.md) for more details.
+
+### `cargotest`
+
+`cargotest` is a small tool which runs `cargo test` on a few sample projects
+(such as `servo`, `ripgrep`, `tokei`, etc.). This runs as part of CI and ensures
+there aren't any significant regressions.
+
+> Example: `./x test src/tools/cargotest`
+
+### Large OSS Project builders
+
+We have CI jobs that build large open-source Rust projects that are used as
+regression tests in CI. Our integration jobs build the following projects:
+
+- [Fuchsia](fuchsia.md)
+- [Rust for Linux](rust-for-linux.md)

src/tests/integration.md

@@ -147,8 +147,8 @@ can be found in the [toolstate documentation].
 
 Rust tests integration with real-world code to catch regressions and make
 informed decisions about the evolution of the language. There are several kinds
-of ecosystem tests, including Crater. See the [Integration testing
-chapter](integration.md) for more details.
+of ecosystem tests, including Crater. See the [Ecosystem testing
+chapter](ecosystem.md) for more details.
 
 ### Performance testing