{do:"subdir"} to select a subdirectory in a script

Signed-off-by: Solomon Hykes <sh.github.6811@hykes.org>

tests/subdir/simple/main.cue

@@ -0,0 +1,29 @@
+package main
+
+hello: {
+	string
+
+	#dagger: compute: [
+		{
+			do:  "fetch-container"
+			ref: "alpine"
+		},
+		{
+			do: "exec"
+			args: ["mkdir", "-p", "/tmp/foo"]
+		},
+		{
+			do: "exec"
+			args: ["sh", "-c", "echo -n world > /tmp/foo/hello"]
+		},
+		{
+			do:  "subdir"
+			dir: "/tmp/foo"
+		},
+		{
+			do:     "export"
+			source: "/hello"
+			format: "string"
+		},
+	]
+}

tests/test.sh

@@ -217,6 +217,11 @@ test::input() {
 }
 
 
+test::subdir() {
+  test::one "Subdir: simple usage" --exit=0 --stdout='{"hello":"world"}' \
+      "$dagger" "${DAGGER_BINARY_ARGS[@]}" compute "$d"/subdir/simple
+}
+
 test::all(){
   local dagger="$1"
 
@@ -231,6 +236,7 @@ test::all(){
   test::exec "$dagger"
   test::export "$dagger"
   test::input "$dagger"
+  test::subdir "$dagger"
 }
 
 case "${1:-all}" in