Run anywhere: no author paths left, and CI that proves it

tools/run_tests.sh defaults QEMU_SRC to a sibling of the checkout, which is where setup_qemu.sh puts it; the two defaults disagreed, so a fresh clone rebuilt nothing and reported a build that was not there. The interpreter list was also reading an empty $PY.

tools/test_bk4819_readback.sh was the last test with the author's paths, and the only one that could not run elsewhere. It now takes QEMU, GDB and ELF from the environment or PATH like the python tests, skips with a reason when one is missing, and says so on a platform whose QEMU cannot make the unix socket it uses.

tools/check_docs.py points UVK5_FW_DIR at a sibling and skips the file:line checks, with a message, when there is no firmware tree -- a fresh clone used to see thirteen failures it could do nothing about.

Added .github/workflows/unit.yml (the fast half of run_tests.sh on every push and PR), requirements-dev.txt for the one pip dependency, and a Dockerfile. Flask is not always installed, so test_webui now skips through setUpModule rather than erroring.

tools/test_bk4819_readback.sh

@@ -13,24 +13,44 @@
 # about alignment, not interrupt semantics.
 set -u
 
-QEMU=${QEMU:-/root/qemu-build/qemu-7.2+dfsg/build/qemu-system-arm}
-ELF=${ELF:-/root/uvk5-port/uvk5-sat/build/CW/nr7y.cw.elf}
 HERE=$(cd "$(dirname "$0")" && pwd)
 SIM=$(dirname "$HERE")
 SRC="$SIM/qemu/py32f071.c"
-QSRC=/root/qemu-build/qemu-7.2+dfsg/hw/arm/py32f071.c
+
+# Same rules as the python tests (tools/uvk5_testenv.py): QEMU, GDB and ELF come from the
+# environment, then PATH, then the checkout -- and a missing one is a SKIP with a reason
+# rather than a failure. These were the author's home paths, which is why this was the one
+# test that could not run anywhere else.
+QEMU=${QEMU:-$(command -v qemu-system-arm || true)}
+GDB=${GDB:-$(command -v gdb-multiarch || command -v arm-none-eabi-gdb || true)}
+QEMU_SRC=${QEMU_SRC:-$SIM/../qemu-7.2}
+QSRC="$QEMU_SRC/hw/arm/py32f071.c"
+if [ -z "${ELF:-}" ]; then
+    for cand in "$SIM"/assets/firmware/*.elf "$SIM"/work/*.elf; do
+        [ -e "$cand" ] && ELF=$cand
+    done
+fi
+for t in "$QEMU" "$GDB" "${ELF:-}"; do
+    [ -n "$t" ] && [ -e "$t" ] || {
+        echo "SKIP  missing ${t:-a prerequisite} (set QEMU, GDB and ELF; see the README Quick start)"
+        exit 0
+    }
+done
+
+# QMP travels over a unix socket here and a Windows QEMU cannot create one: say so rather
+# than letting the launch fail and calling it a firmware problem.
+if ! python3 -c "import socket; socket.socket(socket.AF_UNIX)" 2>/dev/null; then
+    echo "SKIP  no unix sockets on this platform, so -qmp unix: is unavailable"
+    exit 0
+fi
 
 SEED=0x1248
 PORT=1259
 SOCK=/tmp/bk-readback.sock
 IMG=/tmp/bk-readback.img
 
-for t in "$QEMU" "$ELF"; do
-    [ -e "$t" ] || { echo "SKIP  missing $t"; exit 0; }
-done
-
 cp "$SRC" /tmp/bk-readback-orig.c
-trap 'cp /tmp/bk-readback-orig.c "$SRC"; cp "$SRC" "$QSRC" 2>/dev/null || true; rm -f "$IMG" "$SOCK"' EXIT
+trap 'cp /tmp/bk-readback-orig.c "$SRC"; [ -d "$QEMU_SRC/build" ] && cp "$SRC" "$QSRC" 2>/dev/null; rm -f "$IMG" "$SOCK" "$GDBFILE" 2>/dev/null' EXIT
 
 python3 - "$SRC" "$SEED" <<'PY'
 import sys
@@ -42,8 +62,10 @@ if needle not in s:
 open(src, "w", encoding="utf-8").write(s.replace(needle, f"{needle}\n    s->regs[0x0C] = {seed};", 1))
 PY
 
-cp "$SRC" "$QSRC"
-if (cd /root/qemu-build/qemu-7.2+dfsg/build && ninja qemu-system-arm 2>&1 \
+if [ -d "$QEMU_SRC/build" ]; then
+    cp "$SRC" "$QSRC"
+fi
+if [ -d "$QEMU_SRC/build" ] && (cd "$QEMU_SRC/build" && ninja qemu-system-arm 2>&1 \
         | grep -qE 'FAILED|error:'); then
     echo "FAIL  build error"
     exit 1
@@ -59,7 +81,8 @@ sleep 24
 
 # A command file, not a pile of -ex flags: a `commands` block cannot survive being
 # passed that way, and the failure looks exactly like "the firmware never read it".
-cat > /tmp/bk-readback.gdb <<GDB
+GDBFILE=$(mktemp)
+cat > "$GDBFILE" <<GDB
 set confirm off
 set pagination off
 set height 0
@@ -80,7 +103,7 @@ end
 continue
 GDB
 
-GOT=$(timeout 45 gdb-multiarch -batch -x /tmp/bk-readback.gdb "$ELF" 2>/dev/null \
+GOT=$(timeout 45 "$GDB" -batch -x "$GDBFILE" "$ELF" 2>/dev/null \
     | grep -oE 'GOT 0x[0-9A-Fa-f]{4}' | head -1)
 
 kill $QPID 2>/dev/null || true