sausage/userland/brush/source/brush-shell/tests/cases/brush/command_substitution.yaml

name: "Command substitution"
# These cases use only builtins, so they also run under WASI
# (`cargo xtask test integration --wasi`).
cases:
  - name: "Modern and backtick forms"
    stdin: |
      echo "$(echo modern) `echo legacy`"
    expected_exit_code: 0
    expected_stdout: |
      modern legacy
    expected_stderr: ""

  - name: "Trailing newlines are stripped, inner ones kept"
    stdin: |
      x=$(echo -e "a\n\nb\n\n\n")
      echo "[$x]"
      y=$(echo -n abc)
      echo "[$y]"
      z=$(true)
      echo "[$z] ${#z}"
    expected_exit_code: 0
    expected_stdout: |
      [a

      b]
      [abc]
      [] 0
    expected_stderr: ""

  - name: "Nested substitutions"
    stdin: |
      echo "$(echo "outer $(echo "inner $(echo deepest)")")"
    expected_exit_code: 0
    expected_stdout: |
      outer inner deepest
    expected_stderr: ""

  - name: "Exit status of a substitution"
    stdin: |
      x=$(false)
      echo "status: $?"
      x=$(exit 7)
      echo "status: $?"
      x=$(true)
      echo "status: $?"
    expected_exit_code: 0
    expected_stdout: |
      status: 1
      status: 7
      status: 0
    expected_stderr: ""

  - name: "Assignments inside don't leak out"
    stdin: |
      v=1
      out=$(v=2; echo "$v")
      echo "v=$v out=$out"
    expected_exit_code: 0
    expected_stdout: |
      v=1 out=2
    expected_stderr: ""

  - name: "Functions and loops inside"
    stdin: |
      f() { for i in 1 2 3; do echo "$i"; done; }
      all=$(f)
      echo $all
      echo "$all"
    expected_exit_code: 0
    expected_stdout: |
      1 2 3
      1
      2
      3
    expected_stderr: ""

  - name: "Captures a pipeline's output"
    stdin: |
      x=$(echo "a b" | { read -r p q; echo "$q$p"; })
      echo "$x"
    expected_exit_code: 0
    expected_stdout: |
      ba
    expected_stderr: ""

  - name: "Large output"
    stdin: |
      pad=
      for ((i = 0; i < 10; i++)); do pad+=0123456789; done
      x=$(for ((i = 0; i < 1000; i++)); do echo "line $i $pad"; done)
      echo "${#x}"
      echo "${x:0:8}"
      echo "${x: -20}"
    expected_exit_code: 0
    expected_stdout: |
      109889
      line 0 0
      01234567890123456789
    expected_stderr: ""

  - name: "stderr is captured only when redirected"
    stdin: |
      x=$( { echo visible; echo captured >&2; } 2>&1 )
      echo "$x"
    expected_exit_code: 0
    expected_stdout: |
      visible
      captured
    expected_stderr: ""

  - name: "Word splitting of results"
    stdin: |
      set -- $(echo "a  b   c")
      echo "$#"
      set -- "$(echo "a  b   c")"
      echo "$#"
    expected_exit_code: 0
    expected_stdout: |
      3
      1
    expected_stderr: ""

  - name: "Substitutions in arithmetic"
    stdin: |
      echo $(( $(echo 6) * $(echo 7) ))
    expected_exit_code: 0
    expected_stdout: |
      42
    expected_stderr: ""

  - name: "Quotes and dollars inside"
    stdin: |
      echo "pre-$(echo 'mid "quoted" $notvar')-post"
    expected_exit_code: 0
    expected_stdout: |
      pre-mid "quoted" $notvar-post
    expected_stderr: ""

  - name: "Reading a file"
    test_files:
      - path: "data.txt"
        contents: |
          first line
          second line
    stdin: |
      x=$(<data.txt)
      echo "$x"
      y=$(while read -r l; do echo "<$l>"; done < data.txt)
      echo "$y"
    expected_exit_code: 0
    expected_stdout: |
      first line
      second line
      <first line>
      <second line>
    expected_stderr: ""

  - name: "Here-string inside a substitution"
    stdin: |
      x=$(read -r a b <<< "1 2"; echo "$b$a")
      echo "$x"
    expected_exit_code: 0
    expected_stdout: |
      21
    expected_stderr: ""

  - name: "Many substitutions in a loop"
    stdin: |
      s=
      for i in {1..200}; do s+=$(echo -n "$((i % 10))"); done
      echo "${#s} ${s:0:12}"
    expected_exit_code: 0
    expected_stdout: |
      200 123456789012
    expected_stderr: ""

  - name: "Recursion through substitutions"
    stdin: |
      fib() {
        local n=$1
        if (( n < 2 )); then echo "$n"; return; fi
        echo $(( $(fib $((n - 1))) + $(fib $((n - 2))) ))
      }
      fib 12
    expected_exit_code: 0
    expected_stdout: |
      144
    expected_stderr: ""

  - name: "Builtin output"
    stdin: |
      t=$(type -t echo)
      echo "$t"
      k=$(type -t while)
      echo "$k"
    expected_exit_code: 0
    expected_stdout: |
      builtin
      keyword
    expected_stderr: ""