make: move validation to Makefile and add respec test

Author: andreastt

Makefile

@@ -0,0 +1,21 @@
+.DEFAULT_GOAL = test
+.PHONY: test validate respec
+
+VALIDATOR ?= https://validator.w3.org/nu/
+VALIDATOR_OPTS ?= -F laxtype=yes -F parser=html5 -F level=error
+
+curl = curl -sSLf
+respec = respec2html --disable-sandbox -ew
+
+out := $(shell mktemp)
+
+test: validate respec
+
+validate: index.html
+	@$(curl) $(VALIDATOR_OPTS) -F out=gnu -F doc=@$< $(VALIDATOR) | sed -e 's/^"$<"/$</g' >$(out)
+	@cat $(out)
+	@trap 'rm -rf $(out)' EXIT
+	@test -z "$(shell cat $(out))"
+
+respec: index.html
+	@$(respec) -s $< -o /dev/null