Add interval support

Author: JeroenDeDauw

src/Services/TimeValueBuilder.php

@@ -9,6 +9,7 @@
 use EDTF\EdtfValue;
 use EDTF\Model\ExtDate;
 use EDTF\Model\ExtDateTime;
+use EDTF\Model\Interval;
 use EDTF\Model\Season;
 use EDTF\Model\Set;
 
@@ -33,6 +34,13 @@ public function edtfToTimeValues( string $edtfString ): array {
 			);
 		}
 
+		if ( $edtf instanceof Interval ) {
+			return [
+				$this->singleValueEdtfToTimeValue( $edtf->getStartDate() ),
+				$this->singleValueEdtfToTimeValue( $edtf->getEndDate() )
+			];
+		}
+
 		return [
 			$this->singleValueEdtfToTimeValue( $edtf )
 		];

tests/php/Unit/TimeValueBuilderTest.php

@@ -102,9 +102,19 @@ public function testSet(): void {
 
 	public function testSeason(): void {
 		$this->assertEquals(
-			$this->newTimeValue( '+2021-01-00T00:00:00Z', 0, TimeValue::PRECISION_MONTH ),
+			$this->newTimeValue( '+2021-01-00T00:00:00Z', 0, TimeValue::PRECISION_MONTH ), // TODO
 			$this->edtfToTimeValue( '2021-21' )
 		);
 	}
 
+	public function testInterval(): void {
+		$this->assertEquals(
+			[
+				$this->newTimeValue( '+2020-11-00T00:00:00Z', 0, TimeValue::PRECISION_MONTH ),
+				$this->newTimeValue( '+2021-03-00T00:00:00Z', 0, TimeValue::PRECISION_MONTH )
+			],
+			$this->edtfToMultipleTimeValues( '2020-11/2021-03' )
+		);
+	}
+
 }