tests: implement a better integration test framework than shellspec

(for our usecase at least)

test.sh

@@ -0,0 +1,105 @@
+#!/usr/bin/env bash
+
+set -uo pipefail
+
+declare -i FAILED=0
+declare -i SUCCEDED=0
+declare -i RAN=0
+NAME=""
+
+failed_report()
+{
+	echo "++++++++++++++++++++++++++++++++++++++++++++++++++++"
+	echo $NAME
+	echo "++++++++++++++++++++++++++++++++++++++++++++++++++++"
+	echo "++++ Failed test:"
+	cat /tmp/input.minishell
+	echo "++++ Got output:"
+	cat /tmp/got.minishell
+	echo "++++ But expected:"
+	cat /tmp/expected.minishell
+	echo "++++ Diff:"
+	echo "(red is got, green is expected)"
+	diff --color=always /tmp/got.minishell /tmp/expected.minishell
+	echo "++++ Run this to debug:"
+	echo "echo '$(cat /tmp/input.minishell)' | ./minishell"
+}
+
+failed()
+{
+	failed_report >> report.txt
+	echo -n "F"
+	FAILED+=1
+}
+
+succeded()
+{
+	echo -n "."
+	SUCCEDED+=1
+}
+
+assert()
+{
+	diff -q /tmp/got.minishell /tmp/expected.minishell > /dev/null && succeded || failed
+}
+
+when_run()
+{
+	cat > /tmp/input.minishell
+	./minishell &> /tmp/got.minishell < /tmp/input.minishell
+	RAN+=1
+	NAME=$1
+}
+
+expecting()
+{
+	cat > /tmp/expected.minishell
+	assert
+}
+
+setup()
+{
+	rm -f report.txt
+}
+
+finalize()
+{
+	echo
+	echo "$RAN tests ran. $SUCCEDED succeded, $FAILED failed."
+	if [ $SUCCEDED -eq $RAN ];
+	then
+		echo "All integration tests passed!"
+	else
+		echo "cat report.txt"
+		echo "to see details of failed tests"
+	fi
+}
+
+setup
+
+when_run <<EOF "empty inputs returns nothing"
+
+EOF
+expecting <<EOF
+EOF
+
+when_run <<EOF "simple command is parsed"
+echo hello
+EOF
+expecting <<EOF
+ ╰─ t_cmdgroup
+     ├─ t_cmdlist
+     │   ├─ num_cmds = 1
+     │   ╰─ cmd[0]
+     │       ├─ t_cmdlist_item
+     │       │   ╰─ t_pipeline
+     │       │       ├─ num_cmd = 1
+     │       │       ╰─ cmd[0]
+     │       │           ╰─ t_simple_cmd
+     │       │               ├─ words = [echo][hello]
+     │       │               ╰─ (no redirections)
+     │       ╰─ t_operator = END
+     ╰─ (no redirections)
+EOF
+
+finalize