testers.hasPkgConfigModule: Extract and add tests, docs

4 files changed, 87 insertions, 0 deletions

diff --git a/pkgs/build-support/testers/default.nix b/pkgs/build-support/testers/default.nix
index 6ab0ee843cb08..15694162edde3 100644
--- a/pkgs/build-support/testers/default.nix
+++ b/pkgs/build-support/testers/default.nix
@@ -121,4 +121,6 @@
         in
           nixosTesting.simpleTest calledTest;
 
+  hasPkgConfigModule = callPackage ./hasPkgConfigModule/tester.nix { };
+
 }
diff --git a/pkgs/build-support/testers/hasPkgConfigModule/tester.nix b/pkgs/build-support/testers/hasPkgConfigModule/tester.nix
new file mode 100644
index 0000000000000..c8342cdd5c3bf
--- /dev/null
+++ b/pkgs/build-support/testers/hasPkgConfigModule/tester.nix
@@ -0,0 +1,47 @@
+# Static arguments
+{ runCommand, pkg-config }:
+
+# Tester arguments
+{ package,
+  moduleName,
+  testName ? "check-pkg-config-${moduleName}",
+}:
+
+runCommand testName {
+    nativeBuildInputs = [ pkg-config ];
+    buildInputs = [ package ];
+    inherit moduleName;
+    meta = {
+      description = "Test whether ${package.name} exposes pkg-config module ${moduleName}";
+    }
+    # Make sure licensing info etc is preserved, as this is a concern for e.g. cache.nixos.org,
+    # as hydra can't check this meta info in dependencies.
+    # The test itself is just Nixpkgs, with MIT license.
+    // builtins.intersectAttrs
+        {
+          available = throw "unused";
+          broken = throw "unused";
+          insecure = throw "unused";
+          license = throw "unused";
+          maintainers = throw "unused";
+          platforms = throw "unused";
+          unfree = throw "unused";
+          unsupported = throw "unused";
+        }
+        package.meta;
+  } ''
+    echo "checking pkg-config module $moduleName in $buildInputs"
+    set +e
+    version="$(pkg-config --modversion $moduleName)"
+    r=$?
+    set -e
+    if [[ $r = 0 ]]; then
+      echo "✅ pkg-config module $moduleName exists and has version $version"
+      echo "$version" > $out
+    else
+      echo "These modules were available in the input propagation closure:"
+      pkg-config --list-all
+      echo "❌ pkg-config module $moduleName was not found"
+      false
+    fi
+  ''
diff --git a/pkgs/build-support/testers/hasPkgConfigModule/tests.nix b/pkgs/build-support/testers/hasPkgConfigModule/tests.nix
new file mode 100644
index 0000000000000..8005c3f937095
--- /dev/null
+++ b/pkgs/build-support/testers/hasPkgConfigModule/tests.nix
@@ -0,0 +1,36 @@
+# cd nixpkgs
+# nix-build -A tests.testers.hasPkgConfigModule
+{ lib, testers, zlib, runCommand }:
+
+lib.recurseIntoAttrs {
+
+  zlib-has-zlib = testers.hasPkgConfigModule {
+    package = zlib;
+    moduleName = "zlib";
+  };
+
+  zlib-does-not-have-ylib = runCommand "zlib-does-not-have-ylib" {
+    failed = testers.testBuildFailure (
+      testers.hasPkgConfigModule {
+      package = zlib;
+      moduleName = "ylib";
+      }
+    );
+  } ''
+    echo 'it logs a relevant error message'
+    {
+      grep -F "pkg-config module ylib was not found" $failed/testBuildFailure.log
+    }
+
+    echo 'it logs which pkg-config modules are available, to be helpful'
+    {
+      # grep -v: the string zlib does also occur in a store path in an earlier message, which isn't particularly helpful
+      grep -v "checking pkg-config module" < $failed/testBuildFailure.log \
+        | grep -F "zlib"
+    }
+
+    # done
+    touch $out
+  '';
+
+}
diff --git a/pkgs/build-support/testers/test/default.nix b/pkgs/build-support/testers/test/default.nix
index 0a5381b2b738d..313c556737fb3 100644
--- a/pkgs/build-support/testers/test/default.nix
+++ b/pkgs/build-support/testers/test/default.nix
@@ -12,6 +12,8 @@ let
 
 in
 lib.recurseIntoAttrs {
+  hasPkgConfigModule = pkgs.callPackage ../hasPkgConfigModule/tests.nix { };
+
   # Check that the wiring of nixosTest is correct.
   # Correct operation of the NixOS test driver should be asserted elsewhere.
   nixosTest-example = pkgs-with-overlay.testers.nixosTest ({ lib, pkgs, figlet, ... }: {