codeclimate/test-reporter

package cmd

import (
    "encoding/json"
    "os"

    "github.com/codeclimate/test-reporter/formatters"
    "github.com/pkg/errors"
    "github.com/spf13/cobra"
)

type CoverageSummer struct {
    Output string
    Parts  int
}

var summerOptions = CoverageSummer{}

var sumCoverageCmd = &cobra.Command{
    Use:   "sum-coverage",
    Short: "Combine (sum) multiple pre-formatted coverage payloads into one.",
    RunE: func(cmd *cobra.Command, args []string) error {
        if len(args) == 0 {
            return errors.New("you must pass in one or more files to be summarized")
        }
        if summerOptions.Parts != 0 && len(args) != summerOptions.Parts {
            return errors.Errorf("expected %d parts, received %d parts", summerOptions.Parts, len(args))
        }

        rep := formatters.Report{
            SourceFiles: formatters.SourceFiles{},
        }

        f, err := os.Open(args[0])
        if err != nil {
            return errors.WithStack(err)
        }

        err = json.NewDecoder(f).Decode(&rep)
        if err != nil {
            return errors.WithStack(err)
        }

        for _, n := range args[1:] {
            f, err := os.Open(n)
            if err != nil {
                return errors.WithStack(err)
            }

            rr := formatters.Report{
                SourceFiles: formatters.SourceFiles{},
            }

            err = json.NewDecoder(f).Decode(&rr)
            if err != nil {
                return errors.WithStack(err)
            }
            err = rep.Merge(&rr)
            if err != nil {
                return errors.WithStack(err)
            }
        }

        out, err := writer(summerOptions.Output)
        if err != nil {
            return errors.WithStack(err)
        }

        err = rep.Save(out)
        if err != nil {
            return errors.WithStack(err)
        }
        return nil
    },
}

func init() {
    sumCoverageCmd.Flags().IntVarP(&summerOptions.Parts, "parts", "p", 0, "total number of parts to sum")
    sumCoverageCmd.Flags().StringVarP(&summerOptions.Output, "output", "o", ccDefaultCoveragePath, "output path")
    RootCmd.AddCommand(sumCoverageCmd)
}