zasm: clarify strlen's API

apps/zasm/util.asm

@@ -25,6 +25,7 @@ subDEFromHL:
 	ret
 
 ; Returns length of string at (HL) in A.
+; Doesn't include null termination.
 strlen:
 	push	bc
 	push	hl

tools/tests/unit/runtests.sh

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/usr/bin/env bash
 
 set -e
 
@@ -9,12 +9,21 @@ RUNBIN="${TOOLS}/emul/runbin/runbin"
 KERNEL="${BASE}/kernel"
 APPS="${BASE}/apps"
 
-for fn in *.asm; do
-    echo "Running test ${fn}"
-    if ! ${ZASM} "${KERNEL}" "${APPS}" < ${fn} | ${RUNBIN}; then
+chk() {
+    echo "Running test $1"
+    if ! ${ZASM} "${KERNEL}" "${APPS}" < $1 | ${RUNBIN}; then
         echo "failed with code ${PIPESTATUS[1]}"
         exit 1
     fi
+}
+
+if [[ ! -z $1 ]]; then
+    chk $1
+    exit 0
+fi
+
+for fn in *.asm; do
+    chk "${fn}"
 done
 
 echo "All tests passed!"

tools/tests/unit/test_util_z.asm

@@ -5,6 +5,7 @@ jp	test
 #include "zasm/util.asm"
 
 testNum:	.db 1
+sFoo:		.db "foo", 0
 
 test:
 	ld	hl, 0xffff
@@ -18,6 +19,12 @@ test:
 	jp	nz, fail
 	call	nexttest
 
+	ld	hl, sFoo
+	call	strlen
+	cp	3
+	jp	nz, fail
+	call	nexttest
+
 	; success
 	xor	a
 	halt