Tests. To run just call 'make'

You need to ensure that bats-core is installed:
https://github.com/bats-core/bats-core

Makefile

@@ -0,0 +1,9 @@
+default: test
+
+.PHONY: check-bats-exists
+check-bats-exists:
+	@which bats > /dev/null || (echo "Missing dependency. You need to ensure that 'bats' is installed and in your \$$PATH. See https://github.com/bats-core/bats-core" && exit 1)
+
+.PHONY: test
+test: check-bats-exists
+	bats tests/

tests/tests.bats

@@ -0,0 +1,121 @@
+#!/usr/bin/env bats
+#
+# To skip a test, just uncomment the # skip line
+
+@test "-? switch" {
+  # skip
+  run ./ttfb -?
+  [[ "$output" =~ "Usage: " ]]
+}
+
+@test "Invalid switch" {
+  # skip
+  run ./ttfb -Z
+
+  [ $status -ne 0 ]
+  [[ "$output" =~ "Usage: " ]]
+}
+
+@test "-d logs requests to ./curl.log" {
+  # skip
+  rundir="$(mktemp -d)"
+  pwd="$PWD"
+  cd "$rundir" && run "$pwd/ttfb" -d example.com
+  [ $status -eq 0 ]
+  [ -f "$rundir/curl.log" ]
+}
+
+@test "-l logs to specific file" {
+  rundir="$(mktemp -d)"
+  logdir="$(mktemp -d)"
+  pwd="$PWD"
+  cd "$rundir" && run "$pwd/ttfb" -l "$logdir/log.log" example.com
+  [ $status -eq 0 ]
+  [ -f "$logdir/log.log" ]
+}
+
+@test "-l exits if the path the custom log file doesn't exist" {
+  rundir="$(mktemp -d)"
+  logdir="$(mktemp -d)"
+  rmdir "$logdir"
+  pwd="$PWD"
+  cd "$rundir" && run "$pwd/ttfb" -l "$logdir/log.log" example.com
+  [ $status -eq 1 ]
+}
+
+@test "-n expects an argument" {
+  # skip
+  run ./ttfb -n example.com
+  [ $status -ne 0 ]
+  [[ "$output" =~ "Usage: " ]]
+}
+
+@test "-n runs test multiple times" {
+  # skip
+  run ./ttfb -n 3 example.com
+  [ $status -eq 0 ]
+  [[ "$output" =~ "..." ]]
+  [[ "$output" =~ "fastest" ]]
+}
+
+@test "can test multiple urls" {
+  # skip
+  run ./ttfb example.com example.com/hello-world
+  [ $status -eq 0 ]
+  [[ "$output" =~ "example.com" ]]
+  [[ "$output" =~ "example.com/hello-world" ]]
+}
+
+@test "can test multiple urls multiple times" {
+  # skip
+  run ./ttfb -n 3 example.com example.com/hello-world
+  [ $status -eq 0 ]
+  [[ "$output" =~ "..." ]]
+  [[ "$output" =~ "example.com" ]]
+  [[ "$output" =~ "example.com/hello-world" ]]
+}
+
+@test "-d logs requests to multiple urls to multiple log files" {
+  # skip
+  rundir="$(mktemp -d)"
+  pwd="$PWD"
+  cd "$rundir" && run "$pwd/ttfb" -d example.com example.com/hello-world
+  [ $status -eq 0 ]
+  [ -f "$rundir/example_com-curl.log" ]
+  [ -f "$rundir/example_com_hello_world-curl.log" ]
+}
+
+@test "-l logs requests to multiple urls to multiple custom log files" {
+  # skip
+  rundir="$(mktemp -d)"
+  pwd="$PWD"
+  cd "$rundir" && run "$pwd/ttfb" -l "$rundir/custom.log" example.com example.com/hello-world
+  [ $status -eq 0 ]
+  [ -f "$rundir/example_com-custom.log" ]
+  [ -f "$rundir/example_com_hello_world-custom.log" ]
+}
+
+@test "-d logs multiple requests to multiple urls to multiple log files" {
+  # skip
+  rundir="$(mktemp -d)"
+  pwd="$PWD"
+  cd "$rundir" && run "$pwd/ttfb" -n2 -d example.com example.com/hello-world
+  [ $status -eq 0 ]
+  [ -f "$rundir/example_com-curl.log" ]
+  [ -f "$rundir/example_com_hello_world-curl.log" ]
+  [ $(grep " 200 OK" "$rundir/example_com-curl.log" | wc -l) -eq 2 ]
+  [ $(grep " 404 Not Found" "$rundir/example_com_hello_world-curl.log" | wc -l) -eq 2 ]
+}
+
+@test "-d logs multiple requests to multiple urls to multiple custom log files" {
+  # skip
+  rundir="$(mktemp -d)"
+  echo $rundir
+  pwd="$PWD"
+  cd "$rundir" && run "$pwd/ttfb" -n2 -l "$rundir/custom.log" example.com example.com/hello-world
+  [ $status -eq 0 ]
+  [ -f "$rundir/example_com-custom.log" ]
+  [ -f "$rundir/example_com_hello_world-custom.log" ]
+  [ $(grep " 200 OK" "$rundir/example_com-custom.log" | wc -l) -eq 2 ]
+  [ $(grep " 404 Not Found" "$rundir/example_com_hello_world-custom.log" | wc -l) -eq 2 ]
+}