Don't require cram to use bash as its shell

tests/completion_tests/basic/test.t

@@ -1,10 +1,8 @@
-  $ . ../helper.sh
   $ ./main.exe > completion.sh
-  $ . ./completion.sh
-  $ x() { completion_test _basic_complete "$1" "$2"; }
+  $ x() { ../print_completions.sh ./completion.sh _basic_complete "$1" "$2"; }
 
   $ x "basic " \
-  >   "      ^" 
+  >   "      ^"
   --bar
   --baz
   --foo
@@ -29,7 +27,7 @@
   --baz
 
   $ x "basic --bar" \
-  >   "           ^" 
+  >   "           ^"
   --bar
 
   $ x "basic --bar " \
@@ -47,11 +45,12 @@
   --foo
   --help
   -h
+
   $ x "basic --foo --bar" \
   >   "         ^       "
   --foo
 
   $ x "basic --bar --foo" \
-  >   "         ^       " 
+  >   "         ^       "
   --bar
   --baz

tests/completion_tests/dune

@@ -1,3 +1,3 @@
 (cram
- (deps helper.sh)
+ (deps print_completions.sh)
  (applies_to :whole_subtree))

tests/completion_tests/helper.sh → tests/completion_tests/print_completions.sh

@@ -1,5 +1,17 @@
 #!/usr/bin/env bash
 
+# Usage: ./print_completions.sh COMPLETION_SCRIPT COMPLETION_FUNCTION COMMAND_LINE CURSOR_LINE
+# Prints the completion suggestions if a user was to press TAB on a
+# given command line with the cursor at the position indicated by
+# CURSOR_LINE. CURSOR_LINE is expected to be a string where the first
+# non-space character is at the position of the cursor. This is so
+# that test scripts can be formatted with COMMAND_LINE and CURSOR_LINE
+# on separate lines to make it visually clear which character of the
+# command line is under the cursor.
+# COMPLETION_SCRIPT is the name of a script that defines bash
+# completion rules, and COMPLETION_FUNCTION is the name of the
+# function defined in that script registered with `complete`.
+
 set -u
 
 # Print the completion suggestions of a given completion function on
@@ -15,9 +27,9 @@ set -u
 # is lined up with the character in the command line where the cursor
 # is located.
 completion_test() {
-    completion_function="$1"
-    COMP_LINE="$2"
-    cursor_line="$3"
+    local completion_function="$1"
+    local COMP_LINE="$2"
+    local cursor_line="$3"
     read -r -a COMP_WORDS <<< "$COMP_LINE"
     if [ ${#COMP_WORDS[@]} == 1 ]; then
 	COMP_WORDS+=("")
@@ -47,3 +59,14 @@ completion_test() {
     $completion_function "$first_word" "$curr_word" "$prev_word"
     printf "%s\n" "${COMPREPLY[@]}"
 }
+
+main () {
+    local completion_script="$1"
+    local completion_function="$2"
+    local COMP_LINE="$3"
+    local cursor_line="$4"
+    . "$completion_script"
+    completion_test "$completion_function" "$COMP_LINE" "$cursor_line"
+}
+
+main "$1" "$2" "$3" "$4"