fix(tests): try to get code coverage from all packages

Makefile

@@ -167,9 +167,7 @@ benchmark-go:
 
 .PHONY: test-go
 test-go:
-	GO111MODULE=on go test \
-		-cover -coverprofile=coverage.txt -covermode=atomic \
-		./...
+	GO111MODULE=on scripts/gocover.sh
 
 .PHONY: test-js
 test-js: .build/deps-build-node.ok

scripts/gocover.sh

@@ -0,0 +1,16 @@
+#!/usr/bin/env bash
+
+set -e
+
+echo "" > coverage.txt
+
+for d in $(go list ./... | grep -v github.com/prymitive/karma/internal/mapper); do
+    go test \
+        -coverprofile=profile.out \
+        -coverpkg=$(go list ./... | grep -v github.com/prymitive/karma/internal/mapper | tr '\n' ',') \
+        $d 2>&1 | grep -v 'warning: no packages being tested depend on matches for pattern'
+    if [ -f profile.out ]; then
+        cat profile.out >> coverage.txt
+        rm profile.out
+    fi
+done