Add test for `DefaultLastMessageFormatter`

libraries/dateformatter/build.gradle.kts

@@ -36,5 +36,8 @@ android {
         implementation(projects.anvilannotations)
         implementation(libs.datetime)
         ksp(libs.showkase.processor)
+
+        testImplementation(libs.test.junit)
+        testImplementation(libs.test.truth)
     }
 }

libraries/dateformatter/src/main/kotlin/io/element/android/libraries/dateformatter/impl/DefaultLastMessageFormatter.kt

@@ -41,17 +41,17 @@ class DefaultLastMessageFormatter @Inject constructor(
     private val locale: Locale,
 ) : LastMessageFormatter {
     private val onlyTimeFormatter: DateTimeFormatter by lazy {
-        val pattern = DateFormat.getBestDateTimePattern(locale, "HH:mm")
+        val pattern = DateFormat.getBestDateTimePattern(locale, "HH:mm") ?: "HH:mm"
         DateTimeFormatter.ofPattern(pattern)
     }
 
     private val dateWithMonthFormatter: DateTimeFormatter by lazy {
-        val pattern = DateFormat.getBestDateTimePattern(locale, "d MMM")
+        val pattern = DateFormat.getBestDateTimePattern(locale, "d MMM") ?: "d MMM"
         DateTimeFormatter.ofPattern(pattern)
     }
 
     private val dateWithYearFormatter: DateTimeFormatter by lazy {
-        val pattern = DateFormat.getBestDateTimePattern(locale, "dd.MM.yyyy")
+        val pattern = DateFormat.getBestDateTimePattern(locale, "dd.MM.yyyy") ?: "dd.MM.yyyy"
         DateTimeFormatter.ofPattern(pattern)
     }
 
@@ -100,6 +100,6 @@ class DefaultLastMessageFormatter @Inject constructor(
             clock.now().toEpochMilliseconds(),
             DateUtils.DAY_IN_MILLIS,
             DateUtils.FORMAT_SHOW_WEEKDAY
-        ).toString()
+        )?.toString() ?: ""
     }
 }

libraries/dateformatter/src/test/kotlin/io/element/android/libraries/dateformatter/impl/DefaultLastMessageFormatterTest.kt

@@ -0,0 +1,105 @@
+/*
+ * Copyright (c) 2023 New Vector Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.element.android.libraries.dateformatter.impl
+
+import com.google.common.truth.Truth.assertThat
+import io.element.android.libraries.dateformatter.LastMessageFormatter
+import kotlinx.datetime.Instant
+import org.junit.Test
+import java.util.Locale
+
+class DefaultLastMessageFormatterTest {
+
+    @Test
+    fun `test null`() {
+        val now = "1980-04-06T18:35:24.00Z"
+        val formatter = createFormatter(now)
+        assertThat(formatter.format(null)).isEmpty()
+    }
+
+    @Test
+    fun `test epoch`() {
+        val now = "1980-04-06T18:35:24.00Z"
+        val formatter = createFormatter(now)
+        assertThat(formatter.format(0)).isEqualTo("01.01.1970")
+    }
+
+    @Test
+    fun `test now`() {
+        val now = "1980-04-06T18:35:24.00Z"
+        val dat = "1980-04-06T18:35:24.00Z"
+        val formatter = createFormatter(now)
+        assertThat(formatter.format(Instant.parse(dat).toEpochMilliseconds())).isEqualTo("20:35")
+    }
+
+    @Test
+    fun `test one second before`() {
+        val now = "1980-04-06T18:35:24.00Z"
+        val dat = "1980-04-06T18:35:23.00Z"
+        val formatter = createFormatter(now)
+        assertThat(formatter.format(Instant.parse(dat).toEpochMilliseconds())).isEqualTo("20:35")
+    }
+
+    @Test
+    fun `test one minute before`() {
+        val now = "1980-04-06T18:35:24.00Z"
+        val dat = "1980-04-06T18:34:24.00Z"
+        val formatter = createFormatter(now)
+        assertThat(formatter.format(Instant.parse(dat).toEpochMilliseconds())).isEqualTo("20:34")
+    }
+
+    @Test
+    fun `test one hour before`() {
+        val now = "1980-04-06T18:35:24.00Z"
+        val dat = "1980-04-06T17:35:24.00Z"
+        val formatter = createFormatter(now)
+        assertThat(formatter.format(Instant.parse(dat).toEpochMilliseconds())).isEqualTo("19:35")
+    }
+
+    @Test
+    fun `test one day before same time`() {
+        val now = "1980-04-06T18:35:24.00Z"
+        val dat = "1980-04-05T18:35:24.00Z"
+        val formatter = createFormatter(now)
+        // TODO DateUtils.getRelativeTimeSpanString returns null.
+        assertThat(formatter.format(Instant.parse(dat).toEpochMilliseconds())).isEqualTo("")
+    }
+
+    @Test
+    fun `test one month before same time`() {
+        val now = "1980-04-06T18:35:24.00Z"
+        val dat = "1980-03-06T18:35:24.00Z"
+        val formatter = createFormatter(now)
+        assertThat(formatter.format(Instant.parse(dat).toEpochMilliseconds())).isEqualTo("6 Mar")
+    }
+
+    @Test
+    fun `test one year before same time`() {
+        val now = "1980-04-06T18:35:24.00Z"
+        val dat = "1979-04-06T18:35:24.00Z"
+        val formatter = createFormatter(now)
+        assertThat(formatter.format(Instant.parse(dat).toEpochMilliseconds())).isEqualTo("06.04.1979")
+    }
+
+    /**
+     * Create DefaultLastMessageFormatter and set current time to the provided date.
+     */
+    private fun createFormatter(@Suppress("SameParameterValue") currentDate: String): LastMessageFormatter {
+        val clock = FakeClock().also { it.givenInstant(Instant.parse(currentDate)) }
+        return DefaultLastMessageFormatter(clock, Locale.US)
+    }
+}

libraries/dateformatter/src/test/kotlin/io/element/android/libraries/dateformatter/impl/FakeClock.kt

@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2023 New Vector Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.element.android.libraries.dateformatter.impl
+
+import kotlinx.datetime.Clock
+import kotlinx.datetime.Instant
+
+class FakeClock : Clock {
+    private var instant: Instant = Instant.fromEpochMilliseconds(0)
+
+    fun givenInstant(instant: Instant) {
+        this.instant = instant
+    }
+
+    override fun now(): Instant = instant
+}