use crate::validators::{ValidationReport, ValidationResult, Validator};
use polars::prelude::*;
pub struct NotNullValidator;
impl Validator for NotNullValidator {
fn name(&self) -> &'static str {
"NotNull"
}
fn validate(&self, df: &DataFrame, column_name: &str) -> ValidationResult<ValidationReport> {
let series = df.column(column_name)?;
let null_count = series.null_count();
if null_count > 0 {
Ok(ValidationReport {
status: "fail",
details: Some(format!("null_count={}", null_count)),
})
} else {
Ok(ValidationReport {
status: "pass",
details: None,
})
}
}
}
#[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()
}
fn make_int_df(values: &[Option<i32>]) -> DataFrame {
let s = Series::new("col".into(), values.to_vec());
DataFrame::new(vec![s.into()]).unwrap()
}
#[test]
fn passes_when_no_nulls() {
let df = make_str_df(&[Some("a"), Some("b"), Some("c")]);
let validator = NotNullValidator;
let report = validator.validate(&df, "col").unwrap();
assert_eq!(report.status, "pass");
assert!(report.details.is_none());
}
#[test]
fn fails_when_some_nulls() {
let df = make_str_df(&[Some("a"), None, Some("b")]);
let validator = NotNullValidator;
let report = validator.validate(&df, "col").unwrap();
assert_eq!(report.status, "fail");
assert!(report.details.unwrap().contains("null_count=1"));
}
#[test]
fn fails_when_all_nulls() {
let df = make_str_df(&[None, None, None]);
let validator = NotNullValidator;
let report = validator.validate(&df, "col").unwrap();
assert_eq!(report.status, "fail");
assert!(report.details.unwrap().contains("null_count=3"));
}
#[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 = NotNullValidator;
let report = validator.validate(&df, "col").unwrap();
assert_eq!(report.status, "pass");
}
#[test]
fn works_with_integer_column() {
let df = make_int_df(&[Some(1), None, Some(2), Some(3)]);
let validator = NotNullValidator;
let report = validator.validate(&df, "col").unwrap();
assert_eq!(report.status, "fail");
assert!(report.details.unwrap().contains("null_count=1"));
}
}