Cli validation

CLI Validation

Prerequisites

Requirement	How to verify
Source code compiles	Run language-specific build command
Runtime dependencies available	Check PATH, shared libraries
Test input data prepared	Files, directories, or stdin content ready
Evidence directory exists	mkdir -p e2e-evidence

Step 1: Build

Use the appropriate build command for the project language:

# Rust
cargo build --release 2>&1 | tee e2e-evidence/cli-build.txt
BINARY="target/release/TOOL_NAME"

# Go
go build -o ./bin/tool ./cmd/tool 2>&1 | tee e2e-evidence/cli-build.txt
BINARY="./bin/tool"

# Node.js
npm run build 2>&1 | tee e2e-evidence/cli-build.txt
BINARY="node dist/index.js"
# Or if package.json has "bin": BINARY="npx TOOL_NAME"

# Python
pip install -e . 2>&1 | tee e2e-evidence/cli-build.txt
# Find the installed binary name from project config:
#   pyproject.toml  → [project.scripts] section:          TOOL_NAME = "package.module:function"
#   setup.py        → entry_points console_scripts list:  'TOOL_NAME=package.module:function'
#   setup.cfg       → [options.entry_points]:              TOOL_NAME = package.module:function
grep -A10 "\[project\.scripts\]" pyproject.toml 2>/dev/null \
  || grep -A10 "console_scripts" setup.py setup.cfg 2>/dev/null \
  | tee -a e2e-evidence/cli-build.txt
BINARY="TOOL_NAME"   # replace with the name found in the config above
# Or: BINARY="python -m PACKAGE_NAME"

Verify the binary exists and is executable:

# For file-path binaries (Rust, Go, Node.js compiled output):
ls -la $BINARY | tee -a e2e-evidence/cli-build.txt

# For PATH-installed binaries (Python console_scripts, npx wrappers):
which $BINARY | tee -a e2e-evidence/cli-build.txt

Step 2: Help Output

$BINARY --help > e2e-evidence/cli-help.txt 2>&1
echo "Exit code: $?" >> e2e-evidence/cli-help.txt

Verify help output includes:

• Usage syntax
• Available commands or subcommands
• Option descriptions
• At least one example (good CLIs include this)

Step 3: Version Check

$BINARY --version > e2e-evidence/cli-version.txt 2>&1
echo "Exit code: $?" >> e2e-evidence/cli-version.txt

Step 4: Happy Path Execution

Run the primary command with valid arguments:

$BINARY COMMAND ARG1 ARG2 --flag value > e2e-evidence/cli-happy-path.txt 2>&1
echo "Exit code: $?" >> e2e-evidence/cli-happy-path.txt

If the tool produces output files:

$BINARY COMMAND --output output.json ARG1 > e2e-evidence/cli-happy-path.txt 2>&1
echo "Exit code: $?" >> e2e-evidence/cli-happy-path.txt
cp output.json e2e-evidence/cli-output-file.json

Step 5: Error Cases

Invalid flag

$BINARY --nonexistent-flag > e2e-evidence/cli-error-invalid-flag.txt 2>&1
echo "Exit code: $?" >> e2e-evidence/cli-error-invalid-flag.txt

Expected: non-zero exit code, helpful error message on stderr.

Missing required argument

$BINARY COMMAND > e2e-evidence/cli-error-missing-arg.txt 2>&1
echo "Exit code: $?" >> e2e-evidence/cli-error-missing-arg.txt

Expected: non-zero exit code, message indicating which argument is missing.

File not found

$BINARY COMMAND /path/to/nonexistent/file.txt > e2e-evidence/cli-error-no-file.txt 2>&1
echo "Exit code: $?" >> e2e-evidence/cli-error-no-file.txt

Expected: non-zero exit code, clear "file not found" message (not a stack trace).

Permission denied (if applicable)

chmod 000 /tmp/test-readonly-file
$BINARY COMMAND /tmp/test-readonly-file > e2e-evidence/cli-error-permission.txt 2>&1
echo "Exit code: $?" >> e2e-evidence/cli-error-permission.txt
chmod 644 /tmp/test-readonly-file

Step 6: Exit Code Verification

Exit codes must follow conventions:

# Success should exit 0
$BINARY COMMAND valid_args > /dev/null 2>&1
echo "Happy path exit code: $?" | tee e2e-evidence/cli-exit-codes.txt

# Errors should exit non-zero
$BINARY --bad-flag > /dev/null 2>&1
echo "Bad flag exit code: $?" | tee -a e2e-evidence/cli-exit-codes.txt

$BINARY COMMAND missing_file.txt > /dev/null 2>&1
echo "Missing file exit code: $?" | tee -a e2e-evidence/cli-exit-codes.txt

Standard exit codes: 0 = success, 1 = general error, 2 = usage error.

Step 7: Stdin / Pipe Input

If the tool accepts stdin:

echo "input data line 1" | $BINARY COMMAND > e2e-evidence/cli-stdin.txt 2>&1
echo "Exit code: $?" >> e2e-evidence/cli-stdin.txt

$BINARY COMMAND < input-file.txt > e2e-evidence/cli-pipe.txt 2>&1
echo "Exit code: $?" >> e2e-evidence/cli-pipe.txt

Test empty stdin:

echo "" | $BINARY COMMAND > e2e-evidence/cli-empty-stdin.txt 2>&1
echo "Exit code: $?" >> e2e-evidence/cli-empty-stdin.txt

Step 8: Output Format Verification

If the tool outputs structured data (JSON, CSV, table):

# JSON output — verify it parses
$BINARY COMMAND --format json ARG 2>&1 | tee e2e-evidence/cli-json-output.txt
jq . e2e-evidence/cli-json-output.txt > /dev/null 2>&1 && echo "Valid JSON" || echo "INVALID JSON"

# CSV output — verify header and row count
$BINARY COMMAND --format csv ARG 2>&1 | tee e2e-evidence/cli-csv-output.txt
head -1 e2e-evidence/cli-csv-output.txt  # Check header
wc -l e2e-evidence/cli-csv-output.txt    # Check row count

Evidence Standards

GOOD: Full stdout/stderr saved to file, exit code captured, output describes what the command actually produced.

BAD: "Command ran successfully" or "Output looked correct" without saving the actual output.

Every evidence file must contain the FULL command output — exit code alone is not evidence.

Common Failures

Symptom	Likely Cause	Fix
Command not found	Binary not in PATH or not built	Verify build step, use absolute path
Segfault / panic	Null pointer, out-of-bounds, unhandled error	Check error handling in code path
Exit code 0 on error	Error path does not set exit code	Add process.exit(1) / os.Exit(1) / std::process::exit(1)
Garbled output	Binary output mixed with stderr	Separate stdout and stderr in evidence capture
Hangs on stdin	Tool expects stdin but none provided	Pass < /dev/null or provide input
JSON parse error in output	Extra text (warnings, logs) mixed with JSON	Ensure structured output goes to stdout, logs to stderr

PASS Criteria Template

• Binary builds without errors
• --help produces readable, complete usage information (exit code 0)
• --version outputs version string (exit code 0)
• Happy path produces expected output (exit code 0)
• Invalid flag produces helpful error (exit code non-zero)
• Missing argument produces helpful error (exit code non-zero)
• File-not-found produces clear message (exit code non-zero, no stack trace)
• Stdin/pipe input works correctly (if applicable)
• Output format (JSON/CSV) is valid and parseable (if applicable)