Add helper text when dragging filter at a low velocity.

app/src/test/java/org/thoughtcrime/securesms/conversationlist/chatfilter/ProgressVelocityTrackerTest.kt

@@ -0,0 +1,57 @@
+package org.thoughtcrime.securesms.conversationlist.chatfilter
+
+import org.junit.Assert.assertEquals
+import org.junit.Test
+import kotlin.time.Duration.Companion.milliseconds
+import kotlin.time.Duration.Companion.seconds
+
+class ProgressVelocityTrackerTest {
+
+  @Test
+  fun `When I calculate velocity, then I expect 0f`() {
+    val testSubject = ProgressVelocityTracker(3)
+    val actual = testSubject.calculateVelocity()
+    assertEquals("Velocity of an empty tracker should be 0f", 0f, actual)
+  }
+
+  @Test
+  fun `Given a single entry, when I calculate velocity, then I expect 0f`() {
+    val testSubject = ProgressVelocityTracker(3)
+    testSubject.submitProgress(0f, 0.milliseconds)
+    val actual = testSubject.calculateVelocity()
+    assertEquals("Velocity of a tracker with a single element should be 0f", 0f, actual)
+  }
+
+  @Test
+  fun `Given 0f to 1f in 1 second, when I calculate velocity, then I expect a rate of 100 percent per second`() {
+    val testSubject = ProgressVelocityTracker(3)
+    testSubject.submitProgress(0f, 0.milliseconds)
+    testSubject.submitProgress(1f, 1.seconds)
+    val actual = testSubject.calculateVelocity()
+    assertEquals("If we complete the progress in 1 second, then we should have a rate of 1 per thousand milliseconds", 1f, actual)
+  }
+
+  @Test
+  fun `Given 5 entries, when I calculate velocity, then I expect a rate based off the last 3 entries`() {
+    val testSubject = ProgressVelocityTracker(3)
+    val entries = listOf(
+      0.0f to 0.seconds,
+      0.1f to 10.milliseconds,
+      0.2f to 20.milliseconds,
+      0.3f to 40.milliseconds,
+      0.4f to 80.milliseconds
+    )
+
+    entries.forEach { (progress, duration) -> testSubject.submitProgress(progress, duration) }
+
+    val velocityA = testSubject.calculateVelocity()
+
+    testSubject.clear()
+
+    entries.drop(2).forEach { (progress, duration) -> testSubject.submitProgress(progress, duration) }
+
+    val velocityB = testSubject.calculateVelocity()
+
+    assertEquals("Expected the velocities to match.", velocityA, velocityB)
+  }
+}

app/src/test/java/org/thoughtcrime/securesms/conversationlist/chatfilter/RingBufferTest.kt

@@ -0,0 +1,41 @@
+package org.thoughtcrime.securesms.conversationlist.chatfilter
+
+import org.junit.Assert.assertEquals
+import org.junit.Test
+
+class RingBufferTest {
+
+  @Test(expected = IllegalArgumentException::class)
+  fun `Given a negative capacity, when I call the constructor, then I expect an IllegalArgumentException`() {
+    RingBuffer<Int>(-1)
+  }
+
+  @Test
+  fun `Given I enqueue more items than my capacity, when I getSize, then I expect my initial capacity`() {
+    val capacity = 10
+    val testSubject = RingBuffer<Int>(capacity)
+
+    (1..(capacity * 2)).forEach {
+      testSubject.add(it)
+    }
+
+    assertEquals("Capacity should never exceed $capacity items.", capacity, testSubject.size())
+    assertEquals("First item should be 10", 11, testSubject[0])
+    assertEquals("Last item should be 20", 20, testSubject[testSubject.size() - 1])
+  }
+
+  @Test(expected = ArrayIndexOutOfBoundsException::class)
+  fun `when I get, then I expect an ArrayIndexOutOfBoundsException`() {
+    val testSubject = RingBuffer<Int>(10)
+    testSubject[0]
+  }
+
+  @Test
+  fun `Given some added elements, when I get, then I expect the element`() {
+    val testSubject = RingBuffer<Int>(10)
+    val expected = 1
+    testSubject.add(expected)
+    val actual = testSubject[0]
+    assertEquals("Expected get to return $expected", expected, actual)
+  }
+}