Merge coverage per file and line

.buildkite/scripts/run_sonar_scanner.sh

@@ -1,6 +1,12 @@
 #!/bin/bash
+
+source .buildkite/scripts/common.sh
+
 set -euo pipefail
 
+add_bin_path
+with_mage
+
 run_sonar_scanner() {
     local message=""
     echo "--- Download coverage reports and merge them"
@@ -15,7 +21,7 @@ run_sonar_scanner() {
     fi
 
     echo "Merge all coverage reports"
-    .buildkite/scripts/merge_xml.sh
+    mage mergeCoverage
 
     echo "--- Execute sonar scanner CLI"
     /scan-source-code.sh

dev/coverage/coverage.go

@@ -0,0 +1,143 @@
+// Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+// or more contributor license agreements. Licensed under the Elastic License;
+// you may not use this file except in compliance with the Elastic License.
+
+// File partially copied from elastic-package.
+
+package coverage
+
+import (
+	"bytes"
+	"encoding/xml"
+	"fmt"
+	"os"
+)
+
+// GenericCoverage is the root element for a Cobertura XML report.
+type GenericCoverage struct {
+	XMLName   xml.Name       `xml:"coverage"`
+	Version   int64          `xml:"version,attr"`
+	Files     []*GenericFile `xml:"file"`
+	Timestamp int64          `xml:"-"`
+	TestType  string         `xml:",comment"`
+}
+
+type GenericFile struct {
+	Path  string         `xml:"path,attr"`
+	Lines []*GenericLine `xml:"lineToCover"`
+}
+
+type GenericLine struct {
+	LineNumber int64 `xml:"lineNumber,attr"`
+	Covered    bool  `xml:"covered,attr"`
+}
+
+func (c *GenericCoverage) Bytes() ([]byte, error) {
+	out, err := xml.MarshalIndent(&c, "", "  ")
+	if err != nil {
+		return nil, fmt.Errorf("unable to format test results as Coverage: %w", err)
+	}
+
+	var buffer bytes.Buffer
+	buffer.WriteString(xml.Header)
+	buffer.WriteString("\n")
+	buffer.Write(out)
+	return buffer.Bytes(), nil
+}
+
+func (c *GenericFile) merge(b *GenericFile) error {
+	// Merge files
+	for _, coverageLine := range b.Lines {
+		found := false
+		foundId := 0
+		for idx, existingLine := range c.Lines {
+			if existingLine.LineNumber == coverageLine.LineNumber {
+				found = true
+				foundId = idx
+				break
+			}
+		}
+		if !found {
+			c.Lines = append(c.Lines, coverageLine)
+		} else {
+			c.Lines[foundId].Covered = c.Lines[foundId].Covered || coverageLine.Covered
+		}
+	}
+	return nil
+}
+
+// merge merges two coverage reports.
+func (c *GenericCoverage) Merge(other *GenericCoverage) error {
+	// Merge files
+	for _, coverageFile := range other.Files {
+		var target *GenericFile
+		for _, existingFile := range c.Files {
+			if existingFile.Path == coverageFile.Path {
+				target = existingFile
+				break
+			}
+		}
+		if target != nil {
+			if err := target.merge(coverageFile); err != nil {
+				return err
+			}
+		} else {
+			c.Files = append(c.Files, coverageFile)
+		}
+	}
+	return nil
+}
+
+func ReadGenericCoverage(path string) (*GenericCoverage, error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return nil, fmt.Errorf("open failed: %w", err)
+	}
+	defer f.Close()
+
+	dec := xml.NewDecoder(f)
+
+	var coverage GenericCoverage
+	err = dec.Decode(&coverage)
+	if err != nil {
+		return nil, fmt.Errorf("xml decode failed: %w", err)
+	}
+
+	return &coverage, nil
+}
+
+func MergeGenericCoverageFiles(paths []string, output string) error {
+	f, err := os.Create(output)
+	if err != nil {
+		return fmt.Errorf("cannot open file %s to write merged coverage: %w", output, err)
+	}
+	defer f.Close()
+
+	var coverage *GenericCoverage
+	for _, path := range paths {
+		c, err := ReadGenericCoverage(path)
+		if err != nil {
+			return fmt.Errorf("failed to read coverage from %s: %w", path, err)
+		}
+		if coverage == nil {
+			coverage = c
+			continue
+		}
+		err = coverage.Merge(c)
+		if err != nil {
+			return fmt.Errorf("failed to merge coverage from %s: %w", path, err)
+		}
+	}
+
+	d, err := coverage.Bytes()
+	if err != nil {
+		return fmt.Errorf("failed to encode merged coverage: %w", err)
+	}
+
+	_, err = f.Write(d)
+	if err != nil {
+		return fmt.Errorf("cannot write merged coverage to %s: %w", output, err)
+	}
+
+	return nil
+}

dev/coverage/coverage_test.go

@@ -0,0 +1,31 @@
+// Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+// or more contributor license agreements. Licensed under the Elastic License;
+// you may not use this file except in compliance with the Elastic License.
+
+package coverage
+
+import (
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestMergeCoverage(t *testing.T) {
+	coverageFiles, err := filepath.Glob("testdata/test-coverage-*.xml")
+	require.NoError(t, err)
+
+	expectedCoverage, err := ReadGenericCoverage("testdata/expected-test-coverage.xml")
+	require.NoError(t, err)
+
+	output := filepath.Join(t.TempDir(), "coverage-merged.xml")
+
+	err = MergeGenericCoverageFiles(coverageFiles, output)
+	require.NoError(t, err)
+
+	mergedCoverage, err := ReadGenericCoverage(output)
+	require.NoError(t, err)
+
+	assert.EqualValues(t, expectedCoverage, mergedCoverage)
+}

dev/coverage/testdata/expected-test-coverage.xml

@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<coverage version="1">
+  <file path="packages/elastic_package_registry/data_stream/metrics/fields/base-fields.yml">
+    <lineToCover lineNumber="1" covered="false"></lineToCover>
+    <lineToCover lineNumber="2" covered="false"></lineToCover>
+    <lineToCover lineNumber="3" covered="false"></lineToCover>
+    <lineToCover lineNumber="4" covered="false"></lineToCover>
+    <lineToCover lineNumber="5" covered="true"></lineToCover>
+    <lineToCover lineNumber="6" covered="false"></lineToCover>
+    <lineToCover lineNumber="7" covered="false"></lineToCover>
+    <lineToCover lineNumber="8" covered="true"></lineToCover>
+    <lineToCover lineNumber="9" covered="false"></lineToCover>
+    <lineToCover lineNumber="10" covered="false"></lineToCover>
+    <lineToCover lineNumber="11" covered="false"></lineToCover>
+    <lineToCover lineNumber="12" covered="false"></lineToCover>
+  </file>
+  <file path="packages/elastic_package_registry/data_stream/metrics/fields/ecs.yml">
+    <lineToCover lineNumber="1" covered="true"></lineToCover>
+    <lineToCover lineNumber="2" covered="true"></lineToCover>
+    <lineToCover lineNumber="3" covered="true"></lineToCover>
+  </file>
+</coverage>

dev/coverage/testdata/test-coverage-1.xml

@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<coverage version="1">
+  <file path="packages/elastic_package_registry/data_stream/metrics/fields/base-fields.yml">
+    <lineToCover lineNumber="1" covered="false"></lineToCover>
+    <lineToCover lineNumber="2" covered="false"></lineToCover>
+    <lineToCover lineNumber="3" covered="false"></lineToCover>
+    <lineToCover lineNumber="4" covered="false"></lineToCover>
+    <lineToCover lineNumber="5" covered="true"></lineToCover>
+    <lineToCover lineNumber="6" covered="false"></lineToCover>
+    <lineToCover lineNumber="7" covered="false"></lineToCover>
+    <lineToCover lineNumber="8" covered="false"></lineToCover>
+    <lineToCover lineNumber="9" covered="false"></lineToCover>
+    <lineToCover lineNumber="10" covered="false"></lineToCover>
+    <lineToCover lineNumber="11" covered="false"></lineToCover>
+    <lineToCover lineNumber="12" covered="false"></lineToCover>
+  </file>
+  <file path="packages/elastic_package_registry/data_stream/metrics/fields/ecs.yml">
+    <lineToCover lineNumber="1" covered="false"></lineToCover>
+    <lineToCover lineNumber="2" covered="false"></lineToCover>
+    <lineToCover lineNumber="3" covered="false"></lineToCover>
+  </file>
+</coverage>

dev/coverage/testdata/test-coverage-2.xml

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<coverage version="1">
+  <file path="packages/elastic_package_registry/data_stream/metrics/fields/ecs.yml">
+    <lineToCover lineNumber="1" covered="false"></lineToCover>
+    <lineToCover lineNumber="2" covered="false"></lineToCover>
+    <lineToCover lineNumber="3" covered="false"></lineToCover>
+  </file>
+</coverage>

dev/coverage/testdata/test-coverage-3.xml

@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<coverage version="1">
+  <file path="packages/elastic_package_registry/data_stream/metrics/fields/base-fields.yml">
+    <lineToCover lineNumber="1" covered="false"></lineToCover>
+    <lineToCover lineNumber="2" covered="false"></lineToCover>
+    <lineToCover lineNumber="3" covered="false"></lineToCover>
+    <lineToCover lineNumber="4" covered="false"></lineToCover>
+    <lineToCover lineNumber="5" covered="false"></lineToCover>
+    <lineToCover lineNumber="6" covered="false"></lineToCover>
+    <lineToCover lineNumber="7" covered="false"></lineToCover>
+    <lineToCover lineNumber="8" covered="true"></lineToCover>
+    <lineToCover lineNumber="9" covered="false"></lineToCover>
+    <lineToCover lineNumber="10" covered="false"></lineToCover>
+    <lineToCover lineNumber="11" covered="false"></lineToCover>
+    <lineToCover lineNumber="12" covered="false"></lineToCover>
+  </file>
+  <file path="packages/elastic_package_registry/data_stream/metrics/fields/ecs.yml">
+    <lineToCover lineNumber="1" covered="true"></lineToCover>
+    <lineToCover lineNumber="2" covered="true"></lineToCover>
+    <lineToCover lineNumber="3" covered="true"></lineToCover>
+  </file>
+</coverage>

magefile.go

@@ -7,6 +7,7 @@
 package main
 
 import (
+	"fmt"
 	"io"
 	"os"
 	"path/filepath"
@@ -16,6 +17,7 @@ import (
 	"github.com/pkg/errors"
 
 	"github.com/elastic/integrations/dev/codeowners"
+	"github.com/elastic/integrations/dev/coverage"
 )
 
 var (
@@ -51,6 +53,14 @@ func ImportBeats() error {
 	return sh.Run("go", args...)
 }
 
+func MergeCoverage() error {
+	coverageFiles, err := filepath.Glob("build/test-coverage/coverage-*.xml")
+	if err != nil {
+		return fmt.Errorf("glob failed: %w", err)
+	}
+	return coverage.MergeGenericCoverageFiles(coverageFiles, "build/test-coverage/coverage_merged.xml")
+}
+
 func build() error {
 	mg.Deps(buildImportBeats)
 	return nil