chore: Add extract occurences test utility

Extracts timestamps for logs with matching predicates.

homestar-runtime/tests/utils.rs

@@ -1,6 +1,7 @@
 use anyhow::{Context, Result};
 #[cfg(not(windows))]
 use assert_cmd::prelude::*;
+use chrono::{DateTime, FixedOffset};
 #[cfg(not(windows))]
 use nix::{
  sys::signal::{self, Signal},
@@ -95,16 +96,49 @@ pub(crate) fn retrieve_output(proc: Child) -> String {
 pub(crate) fn check_lines_for(output: String, predicates: Vec<&str>) -> bool {
  output
  .split("\n")
- .map(|line| {
- // Line contains all predicates
- predicates
- .iter()
- .map(|pred| predicate::str::contains(*pred).eval(line))
- .fold(true, |acc, curr| acc && curr)
- })
+ .map(|line| check_line_for(line, &predicates))
  .fold(false, |acc, curr| acc || curr)
 }
 
+/// Check process output line for all predicates
+fn check_line_for(line: &str, predicates: &Vec<&str>) -> bool {
+ predicates
+ .iter()
+ .map(|pred| predicate::str::contains(*pred).eval(line))
+ .fold(true, |acc, curr| acc && curr)
+}
+
+/// Extract timestamps for process output lines with matching predicates
+pub(crate) fn extract_occurences_where(
+ output: String,
+ predicates: Vec<&str>,
+) -> Vec<DateTime<FixedOffset>> {
+ output.split("\n").fold(vec![], |mut occurences, line| {
+ if check_line_for(line, &predicates) {
+ match extract_label(&line, "ts=").and_then(|label| {
+ DateTime::parse_from_rfc3339(label).map_or(None, |datetime| Some(datetime))
+ }) {
+ Some(datetime) => {
+ occurences.push(datetime);
+ occurences
+ }
+ None => {
+ panic!("Encountered a log entry that was missing a timestamp label: {line}");
+ }
+ }
+ } else {
+ occurences
+ }
+ })
+}
+
+/// Extract label value from process output line
+fn extract_label<'a>(line: &'a str, key: &str) -> Option<&'a str> {
+ line.split(' ')
+ .find(|label| predicate::str::contains(key).eval(label))
+ .and_then(|label| Some(&label[key.len()..]))
+}
+
 /// Wait for process to exit or kill after timeout.
 pub(crate) fn kill_homestar(mut homestar_proc: Child, timeout: Option<Duration>) -> Child {
  if let Ok(None) = homestar_proc.try_wait() {