testing: script to measure coverage of a binary

Updates #27

build/global.go

@@ -41,7 +41,15 @@ func Generate() {
 		flag.Parse()
 	}
 	cfg := flags.Config()
-	os.Exit(Main(cfg, ctx))
+
+	status := Main(cfg, ctx)
+
+	// To record coverage of integration tests we wrap main() functions in a test
+	// functions. In this case we need the main function to terminate, therefore we
+	// only exit for failure status codes.
+	if status != 0 {
+		os.Exit(status)
+	}
 }
 
 func GP8v() reg.GPVirtual  { return ctx.GP8v() }

script/covermain

@@ -0,0 +1,29 @@
+#!/bin/bash -e
+
+main=$1
+coverprofile=$2
+
+# Temporary working directory.
+workdir=$(mktemp -d)
+
+# Wrap the main function in a go test.
+cp ${main} ${workdir}
+cat > ${workdir}/main_test.go <<EOF
+package main
+
+import "testing"
+
+func TestRunMain(t *testing.T) {
+	main()
+}
+EOF
+
+# Execute the test with coverage.
+testbin="${workdir}/testbin"
+output="${workdir}/cover.out"
+go test -o ${testbin} -covermode=count -coverpkg="github.com/mmcloughlin/avo/..." ${workdir}/*.go
+${testbin} -test.coverprofile=${output}
+cp ${output} ${coverprofile}
+
+# Cleanup.
+rm -rf ${workdir}