Analyst QL

TEST

Testing

While it is certainly possible to test scripts using external coordination, Analyst comes with built-in assertions to faciliate testing of scripts.

It is important to note that tests will only be run in test mode, that is, with the subcommand test rather than run.

Test blocks

The syntax for a test block is as follows:

TEST BLOCK_IDENTIFIER WITH ASSERTIONS (
    ASSERTIONS
)

Where BLOCK_IDENTIFIER is the identifier of the block to be tested (either a source or a transform) and the assertions are semi-colon delimited and chosen from the below:

Assertions

Number of rows overall

Valid assertions are:

  • IT OUTPUTS AT LEAST {N} ROWS
  • IT OUTPUTS AT MOST {N} ROWS
  • IT OUTPUTS EXACTLY {N} ROWS

Number of distinct values, for a given column

  • COLUMN {COLUMN_NAME} HAS AT LEAST {N} DISTINCT VALUES
  • COLUMN {COLUMN_NAME} HAS AT MOST {N} DISTINCT VALUES
  • COLUMN {COLUMN_NAME} HAS EXACTLY {N} DISTINCT VALUES

Uniqueness of a column

The assertion is COLUMN {COLUMN_NAME} HAS UNIQUE VALUES.

No null values

The assertion is COLUMN {COLUMN_NAME} HAS NO NULL VALUES.

Example

The below example contains a passing test and a failing test. Running the test with analyst test --script path/to/file will return an error.

DATA 'Values' (
    [
        ["Hello, World"],
        ["Hello, World"]
    ]
)
INTO CONSOLE
WITH (FORMAT = 'JSON_ARRAY', COLUMNS = 'Word')

TEST Values WITH ASSERTIONS (
    IT OUTPUTS AT LEAST 2 ROWS;
    COLUMN Word HAS UNIQUE VALUES
)
← SET