GitHub Actions: run tests in nix-shell, not Docker

.github/workflows/go.yml

@@ -41,10 +41,9 @@ jobs:
       with:
         go-version: 'stable'
 
-    - name: Build Docker container with the tools our tests require
-      run: |
-        docker build --pull --no-cache --rm -t=router7 -f travis/Dockerfile .
+    - uses: cachix/install-nix-action@v31
+      with:
+        nix_path: nixpkgs=channel:nixos-25.05
 
-    - name: Run tests in Docker container
-      run: |
-        exit=0; for pkg in $(go list ./integration/...); do go test -c $pkg && docker run --privileged --net=host -v $PWD:/usr/src:ro router7 /bin/sh -c "./$(basename $pkg).test -test.v" || exit=1; done; [ $exit = 0 ]
+    - name: Run tests in nix-shell
+      run: nix-shell --command 'make test'

shell.nix

@@ -0,0 +1,11 @@
+{
+  pkgs ? import <nixpkgs> { },
+}:
+pkgs.mkShell {
+  packages = with pkgs; [
+    dnsmasq
+    dig
+    ndisc6
+    nftables
+  ];
+}

travis/Dockerfile

@@ -1,18 +0,0 @@
-# vim:ft=Dockerfile
-FROM debian:sid
-
-RUN echo force-unsafe-io > /etc/dpkg/dpkg.cfg.d/docker-apt-speedup
-# Paper over occasional network flakiness of some mirrors.
-RUN echo 'APT::Acquire::Retries "5";' > /etc/apt/apt.conf.d/80retry
-
-# NOTE: I tried exclusively using gce_debian_mirror.storage.googleapis.com
-# instead of httpredir.debian.org, but the results (Fetched 123 MB in 36s (3357
-# kB/s)) are not any better than httpredir.debian.org (Fetched 123 MB in 34s
-# (3608 kB/s)). Hence, let’s stick with httpredir.debian.org (default) for now.
-
-RUN apt-get update && \
-    DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
-    dnsmasq ndisc6 nftables bind9-dnsutils strace wireguard iproute2 && \
-    rm -rf /var/lib/apt/lists/*
-
-WORKDIR /usr/src

travis/loopmkfs.sh

@@ -1,23 +0,0 @@
-#!/bin/bash
-loopdev=$(sudo losetup -Pf --show /tmp/router7-qemu/disk.img)
-sudo mkfs.ext4 -m 1 "${loopdev}p4"
-sudo mount "${loopdev}p4" /mnt
-# TODO: make github.com/gokrazy/serial-busybox work with GOARCH=amd64
-sudo cp ~/src/busybox-1.22.0-amd64/busybox /mnt/sh || true
-cat <<'EOT' | sudo tee /mnt/interfaces.json
-{
-    "interfaces": [
-	{
-	    "hardware_addr": "52:55:00:d1:55:03",
-	    "name": "uplink0"
-	},
-	{
-	    "hardware_addr": "52:55:00:d1:55:04",
-	    "name": "lan0",
-	    "addr": "10.254.0.1/24"
-	}
-    ]
-}
-EOT
-sudo umount /mnt
-sudo losetup -d "${loopdev}"