test: Add tests for nu shell detection

Rather than using a real fish shell for tests, we're faking it so
package maintainers don't need to add multiple shells as build
dependencies.

lib/proc.sh

@@ -39,8 +39,11 @@ parent_shell() {
 				break
 			fi
 			
-			# If the parent process has "*sh " followed by "-l", it's probably a login shell.
-			if [[ "$target_name" =~ sh\ .*-l ]]; then
+			# If the parent process is one of:
+			#  - `*sh`; or
+			#  - `nu`
+			# Followed by "-l", it's probably a login shell.
+			if [[ "$target_name" =~ ^(.*sh|nu)\ .*-l ]]; then
 				target_name="$(cut -f1 -d' ' <<< "${target_name}")"
 				break
 			fi

src/batpipe.sh

@@ -67,13 +67,13 @@ if [[ "$#" -eq 0 ]]; then
 
 	# Detect the shell.
 	#
-	# This will directly check if the parent is fish, since there's a
-	# good chance that `bash` or `sh` will be invoking fish.
-	if [[ "$(basename -- "$(parent_executable | cut -f1 -d' ')")" == "fish" ]]; then
-		detected_shell="fish"
-	else
-		detected_shell="$(parent_shell)"
-	fi
+	# This will directly check if the parent is a non-sh/bash shell, since
+	# there's a good chance that `bash` or `sh` will be invoking it.
+	case "$(basename -- "$(parent_executable | cut -f1 -d' ')")" in
+		fish) detected_shell="fish" ;;
+		nu)   detected_shell="nu" ;;
+		*)    detected_shell="$(parent_shell)" ;;
+	esac
 
 	# Print the commands required to add `batpipe` to the environment variables.
 	case "$(basename -- "${detected_shell:bash}")" in
@@ -81,6 +81,12 @@ if [[ "$#" -eq 0 ]]; then
 			printc '%{YELLOW}set -x %{CLEAR}LESSOPEN %{CYAN}"|%q %%s"%{CLEAR};\n' "$SELF"
 			printc '%{YELLOW}set -e %{CLEAR}LESSCLOSE;\n'
 			;;
+		nu) # Nushell
+			printc '%{BLUE}$env%{CLEAR}.LESSOPEN = %{CYAN}"|%q %%s"%{CLEAR}\n' "$SELF"
+			if [[ "${LESSCLOSE:-}" != "" ]]; then
+				printc '%{BLUE}hide-env%{CLEAR} LESSCLOSE\n' "$SELF"
+			fi
+			;;
 		*) # Bash-like
 			printc '%{MAGENTA}LESSOPEN%{CLEAR}=%{CYAN}"|%s %%s"%{CLEAR};\n' "$SELF"
 			printc '%{YELLOW}export%{CLEAR} LESSOPEN;\n' "$SELF"
@@ -99,6 +105,10 @@ if [[ "$#" -eq 0 ]]; then
 			printc '%{YELLOW}set -x %{CLEAR}LESS %{CYAN}"%{MAGENTA}$LESS%{CYAN} -R"%{CLEAR};\n' "$SELF"
 			printc '%{YELLOW}set -x %{CLEAR}BATPIPE %{CYAN}"color"%{CLEAR};\n'
 			;;
+		nu) # Nushell
+			printc '%{BLUE}$env%{CLEAR}.LESS = %{CYAN}$"%{MAGENTA}($env.LESS)%{CYAN} -R"%{CLEAR}\n' "$SELF"
+			printc '%{BLUE}$env%{CLEAR}.BATPIPE = %{CYAN}"color"%{CLEAR}\n' "$SELF"
+			;;
 		*) # Bash-like
 			printc '%{MAGENTA}LESS%{CLEAR}=%{CYAN}"%{MAGENTA}$LESS%{CYAN} -R"%{CLEAR};\n' "$SELF"
 			printc '%{MAGENTA}BATPIPE%{CLEAR}=%{CYAN}"color"%{CLEAR};\n' "$SELF"

test/shimexec/fish

@@ -1,14 +1,4 @@
 #!/usr/bin/env bash
-# Find the real fish.
-HERE="$(cd "$(dirname "$0")" && pwd)"
-while read -d ':' -r dir; do
-	if [[ "$dir" == "$HERE" || -z "$dir" ]]; then continue; fi
-	if [[ -f "${dir}/fish" ]]; then
-		TMPDIR='' "${dir}/fish" "$@"
-		exit $?
-	fi
-done <<<"$PATH:"
-
-# Print error and exit.
-echo "fish was not found on \$PATH" 1>&2
-exit 127
+# Run bash, but with executable name as `fish`.
+exec -a "${SHIM_ARGV0:-fish}" bash "$@"
+exit $?

test/shimexec/nu

@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+# Run bash, but with executable name as `nu`.
+#
+# Spawn the process in the background and wait on it to ensure we keep
+# the fake shell as a parent process.
+exec -a "${SHIM_ARGV0:-nu}" bash "$@"
+exit $?

test/snapshot/batgrep/test_output_with_color.stdout.snapshot

@@ -1,8 +1,8 @@
 ────────────────────────────────────────────────────────────────────────────────
      File: file.txt
-   1 cat                                                                        
-   2 dog
-   3 car                                                                        
-   4 frog
-   5 fox
+   1 cat                                                                        
+   2 dog
+   3 car                                                                        
+   4 frog
+   5 fox
 ────────────────────────────────────────────────────────────────────────────────

test/snapshot/batgrep/test_output_without_separator.stdout.snapshot

@@ -1,6 +1,6 @@
      File: file.txt
-   1 cat                                                                        
-   2 dog
-   3 car                                                                        
-   4 frog
-   5 fox
+   1 cat                                                                        
+   2 dog
+   3 car                                                                        
+   4 frog
+   5 fox

test/snapshot/batgrep/test_respects_bat_style.stdout.snapshot

@@ -1,7 +1,7 @@
-────────────────────────────────────────────────────────────────────────────────
+────────────────────────────────────────────────────────────────────────────────
 cat                                                                             
 dog
 car                                                                             
 frog
 fox
-────────────────────────────────────────────────────────────────────────────────
+────────────────────────────────────────────────────────────────────────────────

test/snapshot/batpipe/test_batpipe_term_width.stdout.snapshot

@@ -1,26 +1,26 @@
-───────┬────────────────────────────────
-       │ File: file.txt
-───────┼────────────────────────────────
-   1   │ cat
-   2   │ dog
-   3   │ car
-   4   │ frog
-   5   │ fox
-   6   │ clocks
-   7   │ bash
-   8   │ $300
-   9   │ ^$!@
-───────┴────────────────────────────────
-───────┬────────────────────────────────────────────────────
-       │ File: file.txt
-───────┼────────────────────────────────────────────────────
-   1   │ cat
-   2   │ dog
-   3   │ car
-   4   │ frog
-   5   │ fox
-   6   │ clocks
-   7   │ bash
-   8   │ $300
-   9   │ ^$!@
-───────┴────────────────────────────────────────────────────
+───────┬────────────────────────────────
+       │ File: file.txt
+───────┼────────────────────────────────
+   1   │ cat
+   2   │ dog
+   3   │ car
+   4   │ frog
+   5   │ fox
+   6   │ clocks
+   7   │ bash
+   8   │ $300
+   9   │ ^$!@
+───────┴────────────────────────────────
+───────┬────────────────────────────────────────────────────
+       │ File: file.txt
+───────┼────────────────────────────────────────────────────
+   1   │ cat
+   2   │ dog
+   3   │ car
+   4   │ frog
+   5   │ fox
+   6   │ clocks
+   7   │ bash
+   8   │ $300
+   9   │ ^$!@
+───────┴────────────────────────────────────────────────────

test/suite/batpipe.sh

@@ -11,12 +11,35 @@ test:detected_bash_shell() {
 }
 
 test:detected_fish_shell() {
-	description "Test it can detect a bash shell."
-	command -v "fish" &>/dev/null || skip "Test requires fish shell."
-	fish -c 'exit 0' &>/dev/null || skip "Test requires fish shell." # This is in case it finds "fish" in shimexec dir.
-	
-	output="$(SHELL="fish" fish --login -c "$(batpipe_path)")"
-	grep '^set -x' <<< "$output" >/dev/null || fail "Detected the wrong shell for fish."
+	description "Test it can detect a fish shell."
+
+	# Note: We don't use bash's `-c` option when testing with a fake fish shell.
+	# Bash `-c` will automatically exec() into the last process, which loses the
+	# argv0 we intentionally named after a different shell.
+
+	# Test detection via `*sh -l` parent process.
+	output="$(printf "%q" "$(batpipe_path)" | fish -l)"
+	grep '^set -x' <<< "$output" >/dev/null || fail 'Detected wrong shell when checking parent process args.'
+
+	# Test detection via hypen-prefixed parent process.
+	output="$(printf "%q" "$(batpipe_path)" | SHIM_ARGV0='-fish' fish)"
+	grep '^set -x' <<< "$output" >/dev/null || fail 'Detected wrong shell when checking parent process.'
+}
+
+test:detected_nu_shell() {
+	description "Test it can detect a nushell shell."
+
+	# Note: We don't use bash's `-c` option when testing with a fake nu shell.
+	# Bash `-c` will automatically exec() into the last process, which loses the
+	# argv0 we intentionally named after a different shell.
+
+	# Test detection via `*sh -l` parent process.
+	output="$(printf "%q" "$(batpipe_path)" | nu -l)"
+	grep '^\$env' <<< "$output" >/dev/null || fail 'Detected wrong shell when checking parent process args.'
+
+	# Test detection via hypen-prefixed parent process.
+	output="$(printf "%q" "$(batpipe_path)" | SHIM_ARGV0='-nu' nu -l)"
+	grep '^\$env' <<< "$output" >/dev/null || fail 'Detected wrong shell when checking parent process.'
 }
 
 test:viewer_gzip() {