opgpcard: Replace flagfile with environment variable

- A flagfile requires manual management with touch and rm, replace it
    with an environment variable that can be set more conveniently.

  - Removing tools/tests/opgpcard.rs is not necessary, the file it links
    to is always generated in build.rs, either with subplot tests or
    without. But it is always there, so cargo test does not fail for
    that reason.

.gitlab-ci.yml

@@ -145,8 +145,7 @@ subplot:
   script:
     # make sure a virtual card is available, so that the subplot tests are
     # generated
-    - touch tools/virtual-card-available
-    - cargo test
+    - CARD_BASED_TESTS=true cargo test
   cache:
     # inherit all general cache settings
     <<: *general_cache_config

tools/build.rs

@@ -9,21 +9,23 @@ fn main() {
     // card is available. This is a kludge until Subplot can do
     // conditional scenarios
     // (https://gitlab.com/subplot/subplot/-/issues/20).
-    let flagfile = Path::new("virtual-card-available");
-    if flagfile.exists() {
-        subplot_build::codegen("subplot/opgpcard.subplot")
-            .expect("failed to generate code with Subplot");
-        println!("cargo:warning=generating subplot tests");
-    } else {
-        // If we're not generating code from the subplot, we should at
-        // least create an empty file so that the tests/opgpcard.rs
-        // file can include it. Otherwise the build will fail.
-        println!("cargo:warning=flagfile not found");
-        let out_dir = std::env::var("OUT_DIR").unwrap();
-        let include = Path::new(&out_dir).join("opgpcard.rs");
-        eprintln!("build.rs: include={}", include.display());
-        if !include.exists() {
-            File::create(include).unwrap();
+    match option_env!("CARD_BASED_TESTS") {
+        Some(_) => {
+            subplot_build::codegen("subplot/opgpcard.subplot")
+                .expect("failed to generate code with Subplot");
+            println!("cargo:warning=generated subplot tests");
+        }
+        None => {
+            // If we're not generating code from the subplot, we should at
+            // least create an empty file so that the tests/opgpcard.rs
+            // file can include it. Otherwise the build will fail.
+            println!("cargo:warning=did not generate subplot tests");
+            let out_dir = std::env::var("OUT_DIR").unwrap();
+            let include = Path::new(&out_dir).join("opgpcard.rs");
+            eprintln!("build.rs: include={}", include.display());
+            if !include.exists() {
+                File::create(include).unwrap();
+            }
         }
     }
 }

tools/cargo-test-in-docker

@@ -14,12 +14,12 @@ docker run --rm -it \
 	-v root:/root \
 	-v cargo:/cargo \
 	-v $(pwd):/src \
+	-e CARD_BASED_TESTS=true \
 	registry.gitlab.com/openpgp-card/virtual-cards/smartpgp-builddeps sh -c '
 sed -i "s/timeout=20/timeout=60/" /home/jcardsim/run-card.sh &&
 /etc/init.d/pcscd start &&
 su - -c "sh /home/jcardsim/run-card.sh >/dev/null" jcardsim &&
 cd /src/tools &&
-if ! [ -e virtual-card-available ]; then rm -f tests/opgpcard.rs; fi &&
 CARGO_TARGET_DIR=/cargo/ cargo update &&
 CARGO_TARGET_DIR=/cargo/ cargo build -vv &&
 CARGO_TARGET_DIR=/cargo/ cargo test'

tools/subplot/opgpcard.md

@@ -17,9 +17,9 @@ The verification scenarios in this document assume the availability of
 a virtual smart card. Specifically one described in
 <https://gitlab.com/openpgp-card/virtual-cards>. The
 `openpgp-card/tools` crate is set up to generate tests only if the
-file `tools/virtual-card-available` exists, and the `openpgp-card`
-repository `.gitlab-ci.yml` file is set up to create that file when
-the repository is tested in GitLab CI.
+environment variable `CARD_BASED_TESTS` is set (to any value),
+and the `openpgp-card` repository `.gitlab-ci.yml` file is set up to
+set that environment variable when the repository is tested in GitLab CI.
 
 This means that if you run `cargo test`, no test code is normally
 generated from this document. To run the tests locally, outside of