Coverage Output Formats

Output Formats

Skytest supports five coverage output formats. The format is automatically selected based on the output file extension.

Format Summary

Extension	Format	Use Case	Tools
.txt	Text	Terminal, quick inspection	Human readable
.json	JSON	Custom tooling, APIs	jq, scripts
.xml	Cobertura	CI systems	Jenkins, GitLab, Azure
.lcov	LCOV	IDE extensions	VS Code, genhtml
.html	HTML	Browser viewing	Self-contained

---

Text Format

Human-readable summary for terminal output.

sky.toml

[test.coverage]
enabled = true
output = "coverage.txt"

Output Example

Coverage Report
===============

src/parser.star                                              87.5% (14/16 lines)
  Missing: 23-24
src/lexer.star                                               100.0% (12/12 lines)
src/utils.star                                               66.7% (8/12 lines)
  Missing: 5, 18-20

Total: 85.0% (34/40 lines)

Features

• Per-file coverage percentage
• Line counts (covered/total)
• Missing line numbers displayed as ranges
• Aggregate total at bottom

When to Use

• Quick terminal inspection
• Commit hooks
• Local development feedback

---

JSON Format

Machine-readable format for programmatic access.

sky.toml

[test.coverage]
enabled = true
output = "coverage.json"

Output Example

{
  "timestamp": "2024-01-15T10:30:00Z",
  "total_lines": 40,
  "covered_lines": 34,
  "percentage": 85.0,
  "files": [
    {
      "path": "src/parser.star",
      "total_lines": 16,
      "covered_lines": 14,
      "percentage": 87.5,
      "missing_lines": [23, 24]
    },
    {
      "path": "src/lexer.star",
      "total_lines": 12,
      "covered_lines": 12,
      "percentage": 100.0
    },
    {
      "path": "src/utils.star",
      "total_lines": 12,
      "covered_lines": 8,
      "percentage": 66.67,
      "missing_lines": [5, 18, 19, 20]
    }
  ]
}

Schema Reference

Field	Type	Description
timestamp	string	ISO 8601 timestamp
total_lines	int	Total executable lines
covered_lines	int	Lines executed at least once
percentage	float	Coverage percentage (0-100)
files	array	Per-file coverage data
files[].path	string	File path
files[].missing_lines	array	Line numbers not covered

Processing with jq

# Get overall percentage
jq '.percentage' coverage.json

# List files below 80% coverage
jq '.files[] | select(.percentage < 80) | .path' coverage.json

# Get missing lines for a file
jq '.files[] | select(.path == "src/utils.star") | .missing_lines' coverage.json

When to Use

• Custom dashboards
• Coverage trend analysis
• Integration with internal tools

---

Cobertura XML Format

Standard format supported by most CI platforms.

sky.toml

[test.coverage]
enabled = true
output = "coverage.xml"

Supported Platforms

Jenkins

Cobertura plugin provides coverage reports and trends

GitLab CI

Built-in coverage visualization in merge requests

Azure DevOps

PublishCodeCoverageResults task

Codecov

Full Cobertura format support

Output Example

<?xml version="1.0" encoding="UTF-8"?>
<coverage line-rate="0.8500" branch-rate="0" version="1.0" timestamp="1705312200"
          lines-valid="40" lines-covered="34">
  <sources>
    <source>.</source>
  </sources>
  <packages>
    <package name="src" line-rate="0.8500" branch-rate="0" complexity="0">
      <classes>
        <class name="parser.star" filename="src/parser.star" line-rate="0.8750"
               branch-rate="0" complexity="0">
          <lines>
            <line number="1" hits="1"/>
            <line number="2" hits="3"/>
            <line number="10" hits="5"/>
            <line number="23" hits="0"/>
            <line number="24" hits="0"/>
          </lines>
        </class>
        <class name="lexer.star" filename="src/lexer.star" line-rate="1.0000"
               branch-rate="0" complexity="0">
          <lines>
            <line number="1" hits="2"/>
            <line number="2" hits="2"/>
          </lines>
        </class>
      </classes>
    </package>
  </packages>
</coverage>

XML Element Reference

Element	Attribute	Description
coverage	line-rate	Overall coverage (0.0-1.0)
coverage	lines-valid	Total executable lines
coverage	lines-covered	Covered lines
package	name	Directory/package name
class	filename	Source file path
line	number	Line number (1-based)
line	hits	Execution count

When to Use

• Jenkins with Cobertura plugin
• GitLab CI coverage reports
• Azure DevOps pipelines
• Any CI requiring XML coverage

---

LCOV Format

Tracefile format compatible with genhtml and IDE extensions.

sky.toml

[test.coverage]
enabled = true
output = "coverage.lcov"

Supported Tools

VS Code

Coverage Gutters extension shows inline coverage

JetBrains

Built-in coverage visualization

genhtml

Generate HTML reports from LCOV

SonarQube

Import LCOV for analysis

Output Example

TN:
SF:src/parser.star
FN:10,parse_expression
FNDA:5,parse_expression
FN:25,parse_statement
FNDA:3,parse_statement
FNF:2
FNH:2
DA:1,1
DA:2,3
DA:10,5
DA:11,5
DA:23,0
DA:24,0
LF:16
LH:14
end_of_record
TN:
SF:src/lexer.star
DA:1,2
DA:2,2
DA:3,2
LF:12
LH:12
end_of_record

Field Reference

Field	Format	Description
TN:	TN:<name>	Test name (usually empty)
SF:	SF:<path>	Source file path
FN:	FN:<line>,<name>	Function definition: start line and name
FNDA:	FNDA:<hits>,<name>	Function hit data: call count and name
FNF:	FNF:<count>	Functions found (total)
FNH:	FNH:<count>	Functions hit (covered)
DA:	DA:<line>,<hits>	Line data: line number and hit count
LF:	LF:<count>	Lines found (total)
LH:	LH:<count>	Lines hit (covered)
end_of_record	-	End of file record

Generate HTML with genhtml

# Generate LCOV
skytest --coverage --coverage-output=coverage.lcov tests/

# Convert to HTML
genhtml coverage.lcov --output-directory coverage-html

# Open in browser
open coverage-html/index.html

macOS

brew install lcov

Ubuntu/Debian

apt-get install lcov

Fedora

dnf install lcov

When to Use

• IDE coverage visualization
• VS Code Coverage Gutters
• JetBrains coverage
• Generating detailed HTML with genhtml

---

HTML Format

Self-contained HTML report with embedded CSS. No external dependencies.

sky.toml

[test.coverage]
enabled = true
output = "coverage.html"

Features

• Dark theme - Easy on the eyes
• Collapsible files - Click to expand/collapse per-file details
• Color-coded badges:
  • 🟢 Green: ≥80% coverage
  • 🟡 Yellow: 50-79% coverage
  • 🔴 Red: <50% coverage
• Per-line hit counts - See exactly how many times each line ran
• No external dependencies - Single file, works offline

Output Preview

The HTML report includes:

1. Summary section - Overall percentage, covered/total lines, file count
2. Progress bar - Visual coverage indicator
3. File list - Each file with coverage badge
4. Line details - Expand any file to see line-by-line coverage

┌─────────────────────────────────────────────────┐
│  Coverage Report                                │
│  ═══════════════                                │
│                                                 │
│  ████████████░░░░  85.0%    34 Lines   3 Files  │
│                    Covered                      │
│                                                 │
│  ┌─────────────────────────────────────────┐   │
│  │ src/parser.star          14/16   87.5%  │   │
│  │ ▼ (click to expand)                     │   │
│  │   1  │ 1x │ def parse():                │   │
│  │   2  │ 3x │     token = next()          │   │
│  │  23  │ 0x │     return error  ← RED     │   │
│  └─────────────────────────────────────────┘   │
│  ┌─────────────────────────────────────────┐   │
│  │ src/lexer.star           12/12  100.0%  │   │
│  └─────────────────────────────────────────┘   │
└─────────────────────────────────────────────────┘

Usage

# Generate HTML report
skytest --coverage --coverage-output=coverage.html tests/

# Open in browser
open coverage.html

When to Use

• Sharing coverage with team
• Local development review
• Offline viewing
• No external tool dependencies needed

---

Merging Coverage Reports

Combine coverage from multiple test runs:

# Run different test suites
skytest --coverage --coverage-output=unit.lcov tests/unit/
skytest --coverage --coverage-output=integration.lcov tests/integration/

# Merge with lcov
lcov -a unit.lcov -a integration.lcov -o combined.lcov

# Generate combined report
genhtml combined.lcov -o coverage-html/

Note

Merging combines hit counts, so a line hit once in unit tests and twice in integration tests shows 3 total hits.

---

Format Comparison

Feature	Text	JSON	Cobertura	LCOV	HTML
Human readable	✅	❌	❌	❌	✅
Machine parseable	❌	✅	✅	✅	❌
CI integration	❌	⚠️	✅	⚠️	❌
IDE support	❌	❌	❌	✅	❌
Self-contained	✅	✅	✅	✅	✅
Function coverage	❌	❌	❌	✅	❌
Hit counts	❌	❌	✅	✅	✅