should be it

external/duckdb/test/sqlite/README.md

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+# SQLLogic Test Runner
+
+## Origin
+
+Here you'll find source code originating from
+[SQLite's SQLLogicTest](https://sqlite.org/sqllogictest/doc/trunk/about.wiki).
+DuckDB has extended functionality in several ways, including several new expressions
+(test_env, set/reset, tags).
+
+## Usage Notes
+
+### Environment: test_env and require-env
+
+Environment variables can be managed in 2 ways: `test_env` which allows variables to have defaults set, and `require-env` which is a select/skip predicate for a test file.
+
+For examples of `test_env` usage see the `duckdb/ducklake` extension tests.
+
+When a file `require-env FOO`, or `require-env FOO=bar` a test will only execute if FOO is set, or in the latter case, set to `bar`.
+
+### Tags: explicit and implicit
+
+SQL test files also support a `tags` attribute of the form:
+
+```text
+tags optimization memory>=64GB
+```
+
+The tags are free-form, and can be used when executing tests for both selection and skipping, a la:
+
+```bash
+build/release/test/unittest --skip-tag 'slow' --select-tag-set "['memory>=64GB', 'env[TEST_DATA]']"
+```
+
+Tags can be specified individually, or as a set (which is treated as an `AND` predicate).
+Each specification is an `OR`, and selects are processed before skips.
+
+Additionally some implicit tags are computed when an SQL test file is parsed.
+All `require-env` and `test_env` expressions will be added as tags of the form `env[VAR]`, and
+`env[VAR]=VALUE` (when specified).
+
+For an extensive example of tag matching expectations, see the file
+`test/sqlite/validate_tags_usage.sh` which unit tests these behaviors.