Changed isNewDay to accept null instead of DateTime

Fixes #93

src/TimeKeeper.php

@@ -46,13 +46,15 @@ class TimeKeeper
     /**
      * Returns whether a user who is interating with the game now and last
      * interacted at $lastInteractionTime should experience a New Day event.
-     * @param DateTime $lastInteractionTime
+     * @param DateTime|null $lastInteractionTime
+     * @return bool
      */
-    public function isNewDay(DateTime $lastInteractionTime): bool
+    public function isNewDay(?DateTime $lastInteractionTime): bool
     {
         if ($lastInteractionTime == null) {
             return true;
         }
+
         $t1 = $this->gameTime();
         $t2 = $this->convertToGameTime($lastInteractionTime);
         $d1 = $t1->format("Y-m-d");
@@ -75,9 +77,7 @@ class TimeKeeper
      * @param DateTime $time Game time to convert.
      * @return DateTime Real time corresponding to game time $time.
      */
-    public function convertFromGameTime(
-        DateTime $time
-    ): DateTime {
+    public function convertFromGameTime(DateTime $time): DateTime {
         // Game dates are in the distant past, better not use getTimestamp().
         $i = $this->theBeginning->diff($time);
 
@@ -96,9 +96,7 @@ class TimeKeeper
      * @param DateTime $time Real time to convert.
      * @return DateTime Game time corresponding to real time $time.
      */
-    public function convertToGameTime(
-        DateTime $time
-    ): DateTime {
+    public function convertToGameTime(DateTime $time): DateTime {
         $timeUnix = $time->getTimestamp();
         $epochUnix = $this->adjustedEpoch->getTimestamp();
 

tests/TimeKeeperTest.php

@@ -63,7 +63,25 @@ class TimeKeeperTests extends \PHPUnit_Framework_TestCase {
     $this->assertEquals('0000-01-02', $converted->format('Y-m-d'));
   }
 
-  public function testDetectsNewDay() {
+  public function testIfIsNewDayReturnsTrueWithNullAsLastInteractionTime() {
+      $keeper = new TimeKeeper($this->gameEpoch, $this->gameOffsetSeconds, 4);
+
+      $this->assertTrue($keeper->isNewDay(null));
+  }
+
+  public function testIfIsNewDayReturnsFalseIfLastInteractionTimeWasJustRecently()
+  {
+      // game days per day: 4, each day 6h.
+      $keeper = new TimeKeeper($this->gameEpoch, $this->gameOffsetSeconds, 4);
+
+      $now = new \DateTime();
+      $nowMinus1Second = $now->sub(new \DateInterval("PT1S"));
+      $newMinus1Minute = $now->sub(new \DateInterval("PT1M"));
+      $newMinus1Hour = $now->sub(new \DateInterval("PT1H"));
+      $oldPLus1H = $now->sub(new \DateInterval("PT5H59M59S"));
+
+      $this->assertFalse($keeper->isNewDay($now));
+      $this->assertFalse($keeper->isNewDay($nowMinus1Second));
   }
 
   public function testConvertToRespectsGameOffset() {