Replace chrono with humantime in provenance doc tests. (#175)

Closes #173
Closes #174

Author: molpopgen

Cargo.toml

@@ -33,7 +33,9 @@ serde-pickle = "1.1.0"
 bincode = "1.3.1"
 rand = "0.8.3"
 rand_distr = "0.4.0"
-chrono = "0.4.19"
+humantime = {version = "2.1.0"}
+# chrono is out (for now) due to security issues
+# chrono = "0.4.19"
 
 [build-dependencies]
 bindgen = "0.59.1"

src/provenance.rs

@@ -45,15 +45,9 @@ assert_eq!(record_0, row_0.record);
 let timestamp = prov_ref.timestamp(0).unwrap();
 assert_eq!(timestamp, row_0.timestamp);
 
-// You can get the `chrono::DateTime` object back from the `String`:
-
-let dt = chrono::DateTime::parse_from_rfc3339(&timestamp).unwrap();
-
-// You can get specific time types back, too:
+// You can get the `humantime::Timestamp` object back from the `String`:
 use core::str::FromStr;
-let dt_utc = chrono::DateTime::<chrono::Utc>::from_str(&timestamp).unwrap();
-let dt_local = chrono::DateTime::<chrono::Local>::from_str(&timestamp).unwrap();
-println!("local = {}", dt_local);
+let timestamp_string = humantime::Timestamp::from_str(&timestamp).unwrap();
 
 // Provenance transfers to the tree sequences
 let treeseq = tables.tree_sequence(tskit::TreeSequenceFlags::BUILD_INDEXES).unwrap();
@@ -77,11 +71,9 @@ let record_0 = prov_ref.record(0).unwrap();
 assert_eq!(record_0, row_0.record);
 let timestamp = prov_ref.timestamp(0).unwrap();
 assert_eq!(timestamp, row_0.timestamp);
-let dt = chrono::DateTime::parse_from_rfc3339(&timestamp).unwrap();
 use core::str::FromStr;
-let dt_utc = chrono::DateTime::<chrono::Utc>::from_str(&timestamp).unwrap();
-let dt_local = chrono::DateTime::<chrono::Local>::from_str(&timestamp).unwrap();
-println!("local = {}", dt_local);
+let dt_utc = humantime::Timestamp::from_str(&timestamp).unwrap();
+println!("utc = {}", dt_utc);
 ```
 
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