More execline experiments & testing

Improves the “execline experience” and adds some basic tests.
The idea is that the final result doesn’t use coreutils and provides a
feasible alternative to bash-based tooling.

1 files changed, 86 insertions, 0 deletions

diff --git a/pkgs/profpatsch/execline/run-execline-tests.nix b/pkgs/profpatsch/execline/run-execline-tests.nix
new file mode 100644
index 00000000..c2c4c23e
--- /dev/null
+++ b/pkgs/profpatsch/execline/run-execline-tests.nix
@@ -0,0 +1,86 @@
+{ stdenv, drvSeqL, runExecline
+, ifCommand, redirfdCommand, s6GrepCommand
+, importasCommand, s6TouchCommand, s6CatCommand
+, execlinebCommand, s6TestCommand, s6ChmodCommand
+# https://www.mail-archive.com/skaware@list.skarnet.org/msg01256.html
+, coreutils }:
+
+# TODO: run all of these locally! runExeclineLocal
+
+let
+
+  # lol
+  writeScript = name: script: runExecline {
+    inherit name;
+    derivationArgs = {
+      inherit script;
+      passAsFile = [ "script" ];
+    };
+    execline = ''
+      importas -ui s scriptPath
+      importas -ui out out
+      foreground {
+        ${coreutils}/bin/mv $s $out
+      }
+      ${s6ChmodCommand} 0755 $out
+    '';
+   };
+
+  # execline block of depth 1
+  block = args: builtins.map (arg: " ${arg}") args ++ [ "" ];
+
+  # derivation that tests whether a given line exists
+  # in the given file. Does not use runExecline, because
+  # that should be tested after all.
+  fileHasLine = line: file: derivation {
+    name = "file-${file.name}-has-line";
+    inherit (stdenv) system;
+    builder = ifCommand;
+    args =
+      (block [
+        redirfdCommand "-r" "0" file   # read file to stdin
+        s6GrepCommand "-F" "-q" line      # and grep for the line
+      ])
+      ++ [
+        # if the block succeeded, touch $out
+        importasCommand "-ui" "out" "out"
+        s6TouchCommand "$out"
+      ];
+  };
+
+  # basic test that touches out
+  basic = runExecline {
+    name = "basic";
+    execline = ''
+      importas -ui out out
+      ${s6TouchCommand} $out
+    '';
+  };
+
+  # whether the stdin argument works as intended
+  stdin = fileHasLine "foo" (runExecline {
+    name = "stdin";
+    stdin = "foo\nbar\nfoo";
+    execline = ''
+      importas -ui out out
+      # this pipes stdout of s6-cat to $out
+      # and s6-cat redirects from stdin to stdout
+      redirfd -w 1 $out ${s6CatCommand}
+    '';
+  });
+
+  wrapWithVar = runExecline {
+    name = "wrap-with-var";
+    builderWrapper = writeScript "var-wrapper" ''
+      #!${execlinebCommand} -S0
+      export myvar myvalue $@
+    '';
+    execline = ''
+      importas -ui v myvar
+      if { ${s6TestCommand} myvalue = $v }
+        importas out out
+        ${s6TouchCommand} $out
+    '';
+  };
+
+in args: drvSeqL [ basic stdin wrapWithVar ] (runExecline args)