use crate::validators::{ValidationReport, ValidationResult, Validator};
use chrono::NaiveDateTime;
use polars::prelude::*;
pub struct DateFormatValidator {
pub format: String,
}
impl Validator for DateFormatValidator {
fn name(&self) -> &'static str {
"DateFormat"
}
fn validate(&self, df: &DataFrame, column_name: &str) -> ValidationResult<ValidationReport> {
let series = df.column(column_name)?;
if let Ok(utf8_chunked) = series.str() {
let bad_count = utf8_chunked
.into_iter()
.filter(|opt_val| {
if let Some(val) = opt_val {
NaiveDateTime::parse_from_str(val, &self.format).is_err()
} else {
false }
})
.count();
if bad_count > 0 {
Ok(ValidationReport {
status: "fail",
details: Some(format!("bad_count={}, format={}", bad_count, self.format)),
})
} else {
Ok(ValidationReport {
status: "pass",
details: None,
})
}
} else {
Ok(ValidationReport {
status: "skipped",
details: Some("column is not a string type".to_string()),
})
}
}
}
#[cfg(test)]
mod tests {
use super::*;
fn make_str_df(values: &[Option<&str>]) -> DataFrame {
let s = Series::new("col".into(), values.to_vec());
DataFrame::new(vec![s.into()]).unwrap()
}
#[test]
fn passes_when_all_values_match_format() {
let df = make_str_df(&[Some("2024-01-01 12:00:00"), Some("1999-12-31 23:59:59")]);
let validator = DateFormatValidator {
format: "%Y-%m-%d %H:%M:%S".to_string(),
};
let report = validator.validate(&df, "col").unwrap();
assert_eq!(report.status, "pass");
assert!(report.details.is_none());
}
#[test]
fn fails_when_some_values_do_not_match_format() {
let df = make_str_df(&[
Some("2024-01-01 12:00:00"),
Some("not-a-date"),
Some("2024/01/01 12:00:00"),
]);
let validator = DateFormatValidator {
format: "%Y-%m-%d %H:%M:%S".to_string(),
};
let report = validator.validate(&df, "col").unwrap();
assert_eq!(report.status, "fail");
assert!(report.details.unwrap().contains("bad_count=2"));
}
#[test]
fn ignores_null_values() {
let df = make_str_df(&[Some("2024-01-01 12:00:00"), None]);
let validator = DateFormatValidator {
format: "%Y-%m-%d %H:%M:%S".to_string(),
};
let report = validator.validate(&df, "col").unwrap();
assert_eq!(report.status, "pass");
}
#[test]
fn passes_on_empty_column() {
let s: Series = Series::new("col".into(), Vec::<Option<&str>>::new());
let df = DataFrame::new(vec![s.into()]).unwrap();
let validator = DateFormatValidator {
format: "%Y-%m-%d %H:%M:%S".to_string(),
};
let report = validator.validate(&df, "col").unwrap();
assert_eq!(report.status, "pass");
}
#[test]
fn skips_on_non_string_column() {
let s = Series::new("col".into(), &[1, 2, 3]);
let df = DataFrame::new(vec![s.into()]).unwrap();
let validator = DateFormatValidator {
format: "%Y-%m-%d %H:%M:%S".to_string(),
};
let report = validator.validate(&df, "col").unwrap();
assert_eq!(report.status, "skipped");
assert!(report.details.unwrap().contains("not a string"));
}
}