Add unit tests for DateFormatPattern

app/src/test/java/com/nextcloud/utils/date/DateFormatPatternTest.kt

@@ -0,0 +1,57 @@
+/*
+ * Nextcloud - Android Client
+ *
+ * SPDX-FileCopyrightText: 2026 <Ruba Mogalli> <rubamogalli@gmail.com>
+ * SPDX-License-Identifier: AGPL-3.0-or-later OR GPL-2.0-only
+ */
+package com.nextcloud.utils.date
+
+import org.junit.Assert.assertEquals
+import org.junit.Test
+import java.time.LocalDateTime
+import java.time.format.DateTimeFormatter
+import java.util.Locale
+
+class DateFormatPatternTest {
+
+    // Fixed date, so the result never depends on today's date or timezone
+    private val date = LocalDateTime.of(2024, 8, 3, 14, 38)
+
+    private fun format(pattern: DateFormatPattern): String =
+        DateTimeFormatter.ofPattern(pattern.pattern, Locale.ENGLISH).format(date)
+
+    @Test
+    fun fullDateWithHours_formatsDateAndTime() {
+        assertEquals("03.08.2024 - 14:38", format(DateFormatPattern.FullDateWithHours))
+    }
+
+    @Test
+    fun monthWithDate_formatsShortMonthAndDay() {
+        assertEquals("Aug 3", format(DateFormatPattern.MonthWithDate))
+    }
+
+    @Test
+    fun fullMonthWithYear_formatsFullMonthAndYearAndTime() {
+        assertEquals("August 03, 2024 14:38", format(DateFormatPattern.MonthDayYearTime))
+    }
+
+    @Test
+    fun monthWithYear_formatsShortMonthAndYear() {
+        assertEquals("Aug 2024", format(DateFormatPattern.MonthWithYear))
+    }
+
+    @Test
+    fun fullMonthWithYear_formatsFullMonthAndYear() {
+        assertEquals("August 2024", format(DateFormatPattern.FullMonthWithYear))
+    }
+
+    @Test
+    fun fullMonth_formatsFullMonthName() {
+        assertEquals("August", format(DateFormatPattern.FullMonth))
+    }
+
+    @Test
+    fun year_formatsFourDigitYear() {
+        assertEquals("2024", format(DateFormatPattern.Year))
+    }
+}