test(*): automatically check all binaries, based on binNames

The test list would go out-of-date when new packages were added. This
does the same check as before, but uses the binaries we already
specify on the nix level (via a passthru).

The next step is to try to run the binaries (e.g. with --version),
which will give us a better test of whether they are actually
executable.

.github/workflows/ci.yml

@@ -16,4 +16,4 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       - uses: cachix/install-nix-action@v9
-      - run: ./test.bash
+      - run: ./test.sh

build.nix

@@ -21,6 +21,8 @@ pkgs.stdenv.mkDerivation rec {
 
   nativeBuildInputs = [ pkgs.installShellFiles ];
 
+  passthru.binNames = binNames;
+
   installPhase = ''
     mkdir -p $out/bin
 

test.bash

@@ -1,25 +0,0 @@
-#!/usr/bin/env nix-shell
-#!nix-shell -i bash
-
-ERRORS=0;
-
-function test_exe () {
-  EXE=$1;
-  LOCATION=$(command -v "$EXE");
-  if [ -x "$LOCATION" ]; then
-    echo "found $EXE";
-  else
-    echo "didnt find $EXE";
-    ERRORS=1;
-  fi
-}
-
-test_exe dhall;
-test_exe dhall-to-json;
-test_exe dhall-to-bash;
-test_exe dhall-to-nix;
-test_exe dhall-to-yaml-ng;
-test_exe dhall-docs;
-test_exe dhall-lsp-server;
-
-exit $ERRORS;

test.nix

@@ -0,0 +1,39 @@
+{ pkgs ? import <nixpkgs> {} }:
+
+let
+
+  lib = pkgs.lib;
+
+  executables = lib.concatLists
+    (lib.mapAttrsToList
+      # every package puts its binNames into passthru
+      (_: v: map (bin: "${v}/bin/${bin}") v.passthru.binNames)
+      (import ./default.nix { inherit pkgs; }));
+
+  testExeLocation = pkgs.writers.writeDash "test-exe-location" ''
+    set -e
+    ERRORS=0;
+
+    test_exe () {
+      EXE=$1;
+      LOCATION=$(command -v "$EXE");
+      if [ -x "$LOCATION" ]; then
+        echo "found $EXE";
+      else
+        echo "didnt find $EXE";
+        ERRORS=1;
+      fi
+    }
+
+    for exe in ${lib.escapeShellArgs executables}; do
+      test_exe "$exe"
+    done
+
+    exit "$ERRORS"
+
+  '';
+
+in {
+  inherit
+    testExeLocation;
+}

test.sh

@@ -0,0 +1,4 @@
+#!/usr/bin/env sh
+set -e
+test_script="$(nix-build ./test.nix)"
+exec "$test_script"