MySQL: Tests for time zone handling
PostgreSQL: Tests for time zone handling
SQL Server: Tests for time zone handling
Separate methods to quote different types of literal values
Encode a single quote as two consecutive single quotes
MySQL: Fail more gracefully when time zone info is not loaded
Travis CI: Load MySQL's time zone tables
Represent approximate numeric values using scientific notation

The output of NumberFormatter::create('POSIX', NumberFormatter::SCIENTIFIC)
is more precise and more succinct, but depends on ext-intl.
Only check for assertions in passed tests

Skipped tests are "successful" but not "passed".
Travis CI: Install French locale to test number formatting
Use early return to dispatch in quote_literal()
Represent DateTime as SQL timestamp with time zone
Document method usage/relations
Move literal quoting tests into another file
Move identifier quoting tests into another file
Travis CI: Add builds with error_reporting low and high
Travis CI: Add builds for PHP 5.5
Method to check if a value is an instance of Literal
Quote binary literals according to SQL:1999
Check for a result object before using it

A test can fail before there is any result, e.g. when a @dataProvider
annotation is invalid.