Adopt scripts-to-rule-them-all: script/ entrypoints, Makefile shims

script/test

@@ -0,0 +1,15 @@
+#!/bin/sh
+# script/test: run the test suite (vet first, verbose rerun on failure).
+set -eu
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
+
+main() {
+    cd "$ROOT"
+    # CGO is required (Makefile exports this too)
+    export CGO_ENABLED=1
+    go vet ./...
+    go test ./... || go test -v ./...
+}
+
+main "$@"