feat: allow subplot.md to be used to test an installed Subplot

1 files changed, 48 insertions, 0 deletions

diff --git a/subplot.md b/subplot.md
index d701995..2db50f6 100644
--- a/subplot.md
+++ b/subplot.md
@@ -213,6 +213,54 @@ be good and helpful, writing it will require effort and skill. No tool
 can replace that.
 
 
+
+## Using this document to verify Subplot works
+
+This document ("subplot") can be used to verify Subplot itself from
+its source tree or an installed Subplot. The default is to test
+Subplot from the source tree, and the `./check` script does that. You
+can run this in the source tree to build Subplot and then verify it
+using itself:
+
+~~~sh
+$ cargo build -q
+$ cargo run --bin sp-codegen -- subplot.md -o test.py
+$ python3 test.py
+... much output
+OK, all scenarios finished successfully
+$ 
+~~~
+
+To test an installed Subplot, generate the test program, and tell the
+test program where Subplot is installed. Again, in the Subplot source
+tree:
+
+~~~sh
+$ cargo build -q
+$ cargo run --bin sp-codegen -- subplot.md -o test.py
+$ python3 test.py  --env SUBPLOT_DIR=/usr/local/bin
+... much output
+OK, all scenarios finished successfully
+$ 
+~~~
+
+You can do this with an installed Subplot as well:
+
+~~~sh
+$ cargo clean
+$ /usr/local/bin/sp-codegen subplot.md -o test.py
+$ python3 test.py --env SUBPLOT_DIR=/usr/local/bin
+... much output
+OK, all scenarios finished successfully
+$
+~~~
+
+The generated test program is self-standing, and can be run from
+anywhere. However, to generate it you need to be in the Subplot
+source tree. You can move it elsewhere after generating it, you if you
+prefer.
+
+
 # Requirements
 
 This chapter lists requirements for Subplot. These requirements are