Development
Regex
In certain cases result values might be very large or complex, and we might only be interested in whether or not the result *contains* a snippet of text. In that case, we can use the `<REGEX>:` modifier followed by a certain regex. If the result value matches the regex the test is passed. This is primarily used for query plan analysis.  
```sql
query II
EXPLAIN SELECT tbl.a FROM "data/parquet-testing/arrow/alltypes_plain.parquet" tbl(a) WHERE a = 1 OR a = 2
----
physical_plan<REGEX>:.*PARQUET_SCAN.*Filters: a=1 OR a=2.*
```  
If we instead want the result *not* to contain a snippet of text, we can use the `<!REGEX>:` modifier.