test: add unit tests for TimeUtils

Author: Fandroid745

common/src/main/java/com/ichi2/anki/common/time/TimeUtils.kt

@@ -16,7 +16,6 @@
 
 package com.ichi2.anki.common.time
 
-import com.ichi2.anki.common.annotations.NeedsTest
 import java.text.SimpleDateFormat
 import java.util.Calendar
 import java.util.Locale
@@ -33,11 +32,9 @@ const val TIME_DAY = 24.0 * TIME_HOUR
 // private const val TIME_MONTH = 30.0 * TIME_DAY
 // private const val TIME_YEAR = 12.0 * TIME_MONTH
 
-@NeedsTest("untested")
 fun getTimestamp(time: Time): String = SimpleDateFormat("yyyyMMddHHmmss", Locale.US).format(time.currentDate)
 
 /** Formats the time as '00:00.00' (m:s:ms), OR 00:00:00.00 (h:m:s.ms) */
-@NeedsTest("untested")
 fun Duration.formatAsString(): String {
     val milliseconds = this.inWholeMilliseconds
     val ms = milliseconds % 1000
@@ -51,7 +48,6 @@ fun Duration.formatAsString(): String {
     }
 }
 
-@NeedsTest("untested")
 fun getDayStart(time: Time): Long {
     val cal = time.calendar()
     if (cal[Calendar.HOUR_OF_DAY] < 4) {

common/src/test/java/com/ichi2/anki/common/time/TimeUtilsTest.kt

@@ -19,8 +19,83 @@ import android.icu.util.Calendar
 import org.junit.Assert.assertEquals
 import org.junit.Test
 import java.util.TimeZone
+import kotlin.time.Duration.Companion.hours
+import kotlin.time.Duration.Companion.milliseconds
+import kotlin.time.Duration.Companion.minutes
+import kotlin.time.Duration.Companion.seconds
 
 class TimeUtilsTest {
+    @Test
+    fun getTimeStamp_returnsTimeStampAsUTC() {
+        TimeZone.setDefault(TimeZone.getTimeZone("UTC"))
+        try {
+            val time = MockTime(2020, 7, 7, 7, 0, 0, 0, 0)
+            assertEquals("20200807070000", getTimestamp(time))
+        } finally {
+            TimeZone.setDefault(null)
+        }
+    }
+
+    @Test
+    fun formatAsString_zeroDuration_returnsZeroString() {
+        val duration = 0.milliseconds
+        assertEquals("00:00.00", duration.formatAsString())
+    }
+
+    @Test
+    fun formatAsString_oneMinuteThirtySeconds_returnsOneMinuteThirtySecondsString() {
+        val duration = 1.minutes + 30.seconds + 500.milliseconds
+        assertEquals("01:30.50", duration.formatAsString())
+    }
+
+    @Test
+    fun formatAsString_oneHourDuration_returnsOneHourString() {
+        val duration = 1.hours
+        assertEquals("01:00:00.00", duration.formatAsString())
+    }
+
+    @Test
+    fun formatAsString_overOneHour_returnsHourMinuteSecondString() {
+        val duration = 1.hours + 3.minutes + 4.seconds + 500.milliseconds
+        assertEquals("01:03:04.50", duration.formatAsString())
+    }
+
+    @Test
+    fun getDayStart_BeforeFourAM_returnsDayStart() {
+        TimeZone.setDefault(TimeZone.getTimeZone("UTC"))
+        try {
+            val input = MockTime(2020, 7, 7, 3, 0, 0, 0, 0)
+            val expected = MockTime(2020, 7, 6, 4, 0, 0, 0, 0).calendar().timeInMillis
+            assertEquals(expected, getDayStart(input))
+        } finally {
+            TimeZone.setDefault(null)
+        }
+    }
+
+    @Test
+    fun getDayStart_AfterFourAM_returnsDayStart() {
+        TimeZone.setDefault(TimeZone.getTimeZone("UTC"))
+        try {
+            val input = MockTime(2020, 7, 7, 5, 0, 0, 0, 0)
+            val expected = MockTime(2020, 7, 7, 4, 0, 0, 0, 0).calendar().timeInMillis
+            assertEquals(expected, getDayStart(input))
+        } finally {
+            TimeZone.setDefault(null)
+        }
+    }
+
+    @Test
+    fun getDayStart_AtFourAM_returnsDayStart() {
+        TimeZone.setDefault(TimeZone.getTimeZone("UTC"))
+        try {
+            val input = MockTime(2020, 7, 7, 4, 0, 0, 0, 0)
+            val expected = MockTime(2020, 7, 7, 4, 0, 0, 0, 0).calendar().timeInMillis
+            assertEquals(expected, getDayStart(input))
+        } finally {
+            TimeZone.setDefault(null)
+        }
+    }
+
     @Test
     fun getDayStart_AtJanuary1_returnsDayStart() {
         TimeZone.setDefault(TimeZone.getTimeZone("UTC"))