Add format badge generator

Author: cpl

docs/README.md

@@ -1,6 +1,6 @@
 # `err != nil`
 
-[![err != nil](https://img.shields.io/endpoint?url=https%3A%2F%2Ferrnil.cpl.li%2Fapi%2Fbadge%3Frepo%3Dcpl.li%2Fgo%2Ferrnil%26style%3Dflat-square)](https://errnil.cpl.li/api/inspect?repo=cpl.li/go/errnil)
+[![err != nil](https://img.shields.io/endpoint?url=https%3A%2F%2Ferrnil.cpl.li%2Fapi%2Fbadge%3Frepo%3Dcpl.li%252Fgo%252Ferrnil%26style%3Dflat-square)](https://errnil.cpl.li/api/inspect?repo=cpl.li/go/errnil)
 [![Go Report Card](https://goreportcard.com/badge/cpl.li/go/errnil?style=flat-square)](https://goreportcard.com/report/cpl.li/go/errnil)
 [![Build Status](https://img.shields.io/travis/cpl/errnil/master?style=flat-square)](https://travis-ci.org/cpl/errnil)
 [![Codecov](https://img.shields.io/codecov/c/github/cpl/errnil/master.svg?style=flat-square)](https://codecov.io/gh/cpl/errnil)

pkg/badger/format.go

@@ -0,0 +1,19 @@
+package badger
+
+import (
+	"fmt"
+	"net/url"
+)
+
+func ToMarkdown(repo, style string) string {
+	format := "[![err != nil](https://img.shields.io/endpoint?%s)](https://errnil.cpl.li/api/inspect?repo=%s)"
+
+	badgeURL := url.Values{}
+	badgeURL.Set("repo", repo)
+	badgeURL.Set("style", style)
+
+	endpointURL := url.Values{}
+	endpointURL.Set("url", fmt.Sprintf("https://errnil.cpl.li/api/badge?%s", badgeURL.Encode()))
+
+	return fmt.Sprintf(format, endpointURL.Encode(), repo)
+}

pkg/badger/format_test.go

@@ -0,0 +1,14 @@
+package badger
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_ToMarkdown(t *testing.T) {
+	t.Parallel()
+
+	markdown := ToMarkdown("cpl.li/go/errnil", "flat-square")
+	assert.Equal(t, "[![err != nil](https://img.shields.io/endpoint?url=https%3A%2F%2Ferrnil.cpl.li%2Fapi%2Fbadge%3Frepo%3Dcpl.li%252Fgo%252Ferrnil%26style%3Dflat-square)](https://errnil.cpl.li/api/inspect?repo=cpl.li/go/errnil)", markdown)
+}