doc: move doc to ci readme

.travis.yml

@@ -1,18 +1,4 @@
-# The test build matrix (stage: test) is constructed to test a wide range of
-# configurations, rather than a single pass/fail. This helps to catch build
-# failures and logic errors that present on platforms other than the ones the
-# author has tested.
-#
-# Some builders use the dependency-generator in `./depends`, rather than using
-# apt-get to install build dependencies. This guarantees that the tester is
-# using the same versions as Gitian, so the build results are nearly identical
-# to what would be found in a final release.
-#
-# In order to avoid rebuilding all dependencies for each build, the binaries
-# are cached and re-used when possible. Changes in the dependency-generator
-# will trigger cache-invalidation and rebuilds as necessary.
-#
-# These caches can be manually removed if necessary. This is one of the very
+# Travis caches can be manually removed if necessary. This is one of the very
 # few manual operations that is possible with Travis, and it can be done by a
 # Bitcoin Core GitHub member via the Travis web interface [0].
 #

ci/README.md

@@ -1,12 +1,8 @@
-## ci scripts
+## CI Scripts
 
 This directory contains scripts for each build step in each build stage.
 
-Currently three stages `lint`, `extended_lint` and `test` are defined. Each stage has its own lifecycle, similar to the
-[Travis CI lifecycle](https://docs.travis-ci.com/user/job-lifecycle#the-job-lifecycle). Every script in here is named
-and numbered according to which stage and lifecycle step it belongs to.
-
-### Running a stage locally
+### Running a Stage Locally
 
 Be aware that the tests will be built and run in-place, so please run at your own risk.
 If the repository is not a fresh git clone, you might have to clean files from previous builds or test runs first.
@@ -36,3 +32,34 @@ To run the test stage with a specific configuration,
 ```
 FILE_ENV="./ci/test/00_setup_env_arm.sh" ./ci/test_run_all.sh
 ```
+
+### Configurations
+
+The test files (`FILE_ENV`) are constructed to test a wide range of
+configurations, rather than a single pass/fail. This helps to catch build
+failures and logic errors that present on platforms other than the ones the
+author has tested.
+
+Some builders use the dependency-generator in `./depends`, rather than using
+the system package manager to install build dependencies. This guarantees that
+the tester is using the same versions as the release builds, which also use
+`./depends`.
+
+If no `FILE_ENV` has been specified or values are left out, `00_setup_env.sh`
+is used as the default configuration with fallback values.
+
+It is also possible to force a specific configuration without modifying the
+file. For example,
+
+```
+MAKEJOBS="-j1" FILE_ENV="./ci/test/00_setup_env_arm.sh" ./ci/test_run_all.sh
+```
+
+The files starting with `0n` (`n` greater than 0) are the scripts that are run
+in order.
+
+### Cache
+
+In order to avoid rebuilding all dependencies for each build, the binaries are
+cached and re-used when possible. Changes in the dependency-generator will
+trigger cache-invalidation and rebuilds as necessary.