Testing

Testing guidelines for Trial Submission Studio contributions.

Test Types

Unit Tests

Test individual functions and methods:

#![allow(unused)]
fn main() {
#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn normalize_column_name_removes_spaces() {
        let result = normalize_column_name("Patient Age");
        assert_eq!(result, "PATIENT_AGE");
    }
}
}

Integration Tests

Test interactions between modules:

#![allow(unused)]
fn main() {
// tests/integration_test.rs
use tss_ingest::CsvReader;
use tss_validate::Validator;

#[test]
fn validate_imported_data() {
    let data = CsvReader::read("tests/data/sample.csv").unwrap();
    let results = Validator::validate(&data, "DM").unwrap();
    assert!(results.errors().is_empty());
}
}

Snapshot Tests

Use insta for output stability:

#![allow(unused)]
fn main() {
use insta::assert_snapshot;

#[test]
fn export_produces_expected_output() {
    let output = export_to_string(&data);
    assert_snapshot!(output);
}
}

Property Tests

Use proptest for edge cases:

#![allow(unused)]
fn main() {
use proptest::prelude::*;

proptest! {
    #[test]
    fn similarity_is_symmetric(a in ".*", b in ".*") {
        let ab = calculate_similarity(&a, &b);
        let ba = calculate_similarity(&b, &a);
        assert!((ab - ba).abs() < 0.001);
    }
}
}

Running Tests

All Tests

cargo test

Specific Crate

cargo test --package xport

Specific Test

cargo test test_name

With Output

cargo test -- --nocapture

Release Mode

cargo test --release

Test Organization

File Structure

crates/tss-validate/
├── src/
│   ├── lib.rs
│   └── rules/
│       └── structural.rs
└── tests/
    ├── structural_rules_test.rs
    └── data/
        └── sample_dm.csv

Inline Tests

For simple unit tests:

#![allow(unused)]
fn main() {
// src/normalize.rs

pub fn normalize(s: &str) -> String {
    s.trim().to_uppercase()
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_normalize() {
        assert_eq!(normalize("  hello  "), "HELLO");
    }
}
}

External Tests

For integration tests:

#![allow(unused)]
fn main() {
// tests/validation_integration.rs

use tss_validate::*;

#[test]
fn full_validation_workflow() {
    // Integration test code
}
}

Test Data

Location

Test data files are in:

• mockdata/ - Shared test datasets
• crates/*/tests/data/ - Crate-specific test data

Sample Data

STUDYID,DOMAIN,USUBJID,SUBJID,AGE,SEX
ABC123,DM,ABC123-001,001,45,M
ABC123,DM,ABC123-002,002,38,F

Sensitive Data

Never commit real clinical trial data. Use:

• Synthetic/mock data only
• Anonymized examples
• Generated test cases

Writing Good Tests

Structure (AAA Pattern)

#![allow(unused)]
fn main() {
#[test]
fn test_validation_rule() {
    // Arrange - set up test data
    let data = create_test_dataframe();
    let validator = Validator::new();

    // Act - perform the operation
    let results = validator.validate(&data);

    // Assert - verify results
    assert_eq!(results.len(), 1);
    assert_eq!(results[0].severity, Severity::Error);
}
}

Descriptive Names

#![allow(unused)]
fn main() {
// Good
#[test]
fn returns_error_when_usubjid_is_missing() { ... }

#[test]
fn accepts_valid_iso8601_date_format() { ... }

// Avoid
#[test]
fn test1() { ... }

#[test]
fn it_works() { ... }
}

Test Edge Cases

#![allow(unused)]
fn main() {
#[test]
fn handles_empty_dataframe() { ... }

#[test]
fn handles_null_values() { ... }

#[test]
fn handles_unicode_characters() { ... }

#[test]
fn handles_maximum_length_values() { ... }
}

Test Error Conditions

#![allow(unused)]
fn main() {
#[test]
fn returns_error_for_invalid_input() {
    let result = process_file("nonexistent.csv");
    assert!(result.is_err());
}

#[test]
fn error_contains_helpful_message() {
    let err = process_file("bad.csv").unwrap_err();
    assert!(err.to_string().contains("parse error"));
}
}

Snapshot Testing

With Insta

#![allow(unused)]
fn main() {
use insta::assert_snapshot;

#[test]
fn xpt_header_format() {
    let header = generate_header(&metadata);
    assert_snapshot!(header);
}
}

Updating Snapshots

# Review and update snapshots
cargo insta review

CI Testing

Automated Checks

Every PR runs:

1. cargo test - All tests
2. cargo clippy - Linting
3. cargo fmt --check - Formatting

Test Matrix

Tests run on:

• Ubuntu (primary)
• macOS (future)
• Windows (future)

Test Coverage

Goal

Aim for high coverage on critical paths:

• Validation rules
• Data transformations
• File I/O

Not Required

100% coverage isn’t required. Focus on:

• Business logic
• Error handling
• Edge cases

Next Steps

• Pull Requests - Submit your changes
• Coding Standards - Code style