diff --git a/vector/src/test/java/im/vector/riotx/features/home/room/detail/composer/rainbow/RainbowGeneratorTest.kt b/vector/src/test/java/im/vector/riotx/features/home/room/detail/composer/rainbow/RainbowGeneratorTest.kt
new file mode 100644
index 0000000000..521fb15bf2
--- /dev/null
+++ b/vector/src/test/java/im/vector/riotx/features/home/room/detail/composer/rainbow/RainbowGeneratorTest.kt
@@ -0,0 +1,102 @@
+/*
+ * Copyright 2020 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 im.vector.riotx.features.home.room.detail.composer.rainbow
+
+import org.junit.Assert.assertEquals
+import org.junit.Test
+
+class RainbowGeneratorTest {
+
+ private val rainbowGenerator = RainbowGenerator()
+
+ @Test
+ fun testEmpty() {
+ assertEquals("", rainbowGenerator.generate(""))
+ }
+
+ @Test
+ fun testAscii1() {
+ assertEquals("""a""", rainbowGenerator.generate("a"))
+ }
+
+ @Test
+ fun testAscii2() {
+ val expected =
+ """
+ T
+ h
+ i
+ s
+
+ i
+ s
+
+ a
+
+ r
+ a
+ i
+ n
+ b
+ o
+ w
+ !
+ """
+ .trimIndent()
+ .replace("\n", "")
+
+ assertEquals(expected, rainbowGenerator.generate("This is a rainbow!"))
+ }
+
+ @Test
+ fun testEmoji1() {
+ assertEquals("""\uD83E\uDD1E""", rainbowGenerator.generate("\uD83E\uDD1E")) // 🤞
+ }
+
+ @Test
+ fun testEmoji2() {
+ assertEquals("""🤞""", rainbowGenerator.generate("🤞"))
+ }
+
+ @Test
+ fun testEmojiMix() {
+ val expected = """
+ T
+ h
+ i
+ s
+
+ i
+ s
+
+ a
+
+ r
+ a
+ i
+ n
+ b
+ o
+ w
+ !
+ """
+ .trimIndent()
+ .replace("\n", "")
+
+ assertEquals(expected, rainbowGenerator.generate("Hello 🤞 world!"))
+ }
+}
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