{

private function enum(string $name, array $labels): string

{

$quoted = array_map(static fn($l) => "'" . str_replace("'", "''", $l) . "'", $labels);

return 'CREATE TYPE "' . $name . '" AS ENUM (' . implode(', ', $quoted) . ')';

}

private function sqlFor(array $sourceLabels, array $targetLabels): AlterEnumSQL

{

return new AlterEnumSQL(new AlterEnum(

'order_state',

$this->enum('order_state', $sourceLabels),

$this->enum('order_state', $targetLabels)

));

}

// ── Adding a label ───────────────────────────────────────────────────────

public function testAppendedLabelIsAddedRatherThanReplacingTheType(): void

{

// The target is behind; making it match the source appends one label.

$sql = $this->sqlFor(['new', 'paid', 'shipped'], ['new', 'paid'])->getUp();

$this->assertStringContainsString("ADD VALUE IF NOT EXISTS 'shipped'", $sql);

$this->assertStringNotContainsString('DROP TYPE', $sql);

$this->assertStringNotContainsString('CREATE TYPE', $sql);

}

public function testAppendedLabelIsPositionedAfterItsNeighbour(): void

{

$sql = $this->sqlFor(['new', 'paid', 'shipped'], ['new', 'paid'])->getUp();

$this->assertStringContainsString("ADD VALUE IF NOT EXISTS 'shipped' AFTER 'paid';", $sql);

}

public function testLabelInsertedInTheMiddleKeepsItsPlaceInTheOrdering(): void

{

// BEFORE/AFTER has been available since PostgreSQL 12, so a label does

// not have to go on the end.

$sql = $this->sqlFor(['a', 'b', 'c'], ['a', 'c'])->getUp();

$this->assertStringContainsString("ADD VALUE IF NOT EXISTS 'b' AFTER 'a';", $sql);

$this->assertStringNotContainsString('DROP TYPE', $sql);

}

public function testLabelAddedAtTheFrontAnchorsToTheOneAfterIt(): void

{

$sql = $this->sqlFor(['first', 'a', 'b'], ['a', 'b'])->getUp();

$this->assertStringContainsString("ADD VALUE IF NOT EXISTS 'first' BEFORE 'a';", $sql);

}

public function testSeveralAddedLabelsEachGetAStatement(): void

{

$sql = $this->sqlFor(['a', 'b', 'c', 'd'], ['a', 'c'])->getUp();

$this->assertSame(2, substr_count($sql, 'ADD VALUE'));

$this->assertStringContainsString("'b' AFTER 'a'", $sql);

$this->assertStringContainsString("'d' AFTER 'c'", $sql);

$this->assertStringNotContainsString('DROP TYPE', $sql);

}

public function testAddedLabelsAreIdempotent(): void

{

// IF NOT EXISTS, so re-running a migration is not an error.

$sql = $this->sqlFor(['a', 'b'], ['a'])->getUp();

$this->assertStringContainsString('ADD VALUE IF NOT EXISTS', $sql);

}

public function testALabelWithAQuoteIsEscaped(): void

{

$sql = $this->sqlFor(['a', "it's"], ['a'])->getUp();

$this->assertStringContainsString("ADD VALUE IF NOT EXISTS 'it''s'", $sql);

}

// ── Removing or reordering, which ADD VALUE cannot do ────────────────────

public function testRemovedLabelStillReplacesTheType(): void

{

// There is no DROP VALUE. Doing this properly means migrating every

// dependent column, which cannot be generated blind.

$sql = $this->sqlFor(['a'], ['a', 'b'])->getUp();

$this->assertStringContainsString('DROP TYPE', $sql);

$this->assertStringContainsString('CREATE TYPE', $sql);

}

public function testReplacementSaysWhyItMayNotApply(): void

{

$sql = $this->sqlFor(['a'], ['a', 'b'])->getUp();

$this->assertStringContainsString('while any column still uses it', $sql);

}

public function testReorderedLabelsReplaceTheType(): void

{

// ADD VALUE cannot move a label that already exists.

$sql = $this->sqlFor(['b', 'a'], ['a', 'b'])->getUp();

$this->assertStringContainsString('DROP TYPE', $sql);

}

// ── The two directions are decided separately ────────────────────────────

public function testRevertingAnAdditionReplacesTheType(): void

{

// UP adds a label; DOWN would have to remove it, which it cannot.

$alter = $this->sqlFor(['new', 'paid', 'shipped'], ['new', 'paid']);

$this->assertStringContainsString('ADD VALUE', $alter->getUp());

$this->assertStringContainsString('DROP TYPE', $alter->getDown());

}

public function testDownIsAdditiveWhenTheTargetIsTheOneAhead(): void

{

// The source is behind here, so restoring the target appends.

$alter = $this->sqlFor(['new'], ['new', 'paid']);

$this->assertStringContainsString('DROP TYPE', $alter->getUp());

$this->assertStringContainsString("ADD VALUE IF NOT EXISTS 'paid'", $alter->getDown());

}

// ── Parsing ──────────────────────────────────────────────────────────────

public function testLabelsAreReadOutOfADefinition(): void

{

$this->assertSame(

['new', 'paid'],

EnumLabels::of($this->enum('t', ['new', 'paid']))

);

}

public function testADoubledQuoteIsOneEscapedQuote(): void

{

$this->assertSame(["it's"], EnumLabels::of("CREATE TYPE \"t\" AS ENUM ('it''s')"));

}

public function testACommaInsideALabelIsNotASeparator(): void

{

$this->assertSame(['a,b'], EnumLabels::of("CREATE TYPE \"t\" AS ENUM ('a,b')"));

}

public function testAnUnparseableDefinitionFallsBackRatherThanGuessing(): void

{

$this->assertNull(EnumLabels::of('CREATE DOMAIN "d" AS integer'));

// And the generator takes the replacement path for it.

$sql = (new AlterEnumSQL(new AlterEnum('d', 'CREATE DOMAIN "d" AS integer', 'CREATE DOMAIN "d" AS bigint')))->getUp();

$this->assertStringContainsString('DROP TYPE', $sql);

}

// ── The positioning helper ───────────────────────────────────────────────

public function testAdditionsReturnsNullWhenALabelWasRemoved(): void

{

$this->assertNull(AlterEnumSQL::additions(['a', 'b'], ['a']));

}

public function testAdditionsReturnsEmptyWhenNothingChanged(): void

{

$this->assertSame([], AlterEnumSQL::additions(['a', 'b'], ['a', 'b']));

}

public function testAdditionsAnchorsEachNewLabelToOneThatExists(): void

{

$this->assertSame(

[['b', 'AFTER', 'a'], ['d', 'AFTER', 'c']],

AlterEnumSQL::additions(['a', 'c'], ['a', 'b', 'c', 'd'])

);

}