Replace shortNumber() with formatNumber() (#3519)

formatNumber() was existing code to show numbers with suffixes like K, M, etc, so re-use that code and delete shortNumber().

Update the tests to (a) test formatNumber(), and (b) be parameterised.

app/src/test/java/com/keylesspalace/tusky/util/NumberUtilsTest.kt

@@ -1,49 +1,70 @@
 package com.keylesspalace.tusky.util
 
+import org.junit.AfterClass
 import org.junit.Assert
+import org.junit.BeforeClass
 import org.junit.Test
+import org.junit.runner.RunWith
+import org.junit.runners.Parameterized
+import java.util.Locale
 import kotlin.math.pow
 
-class NumberUtilsTest {
+@RunWith(Parameterized::class)
+class NumberUtilsTest(private val input: Long, private val want: String) {
+    companion object {
+        /** Default locale before this test started */
+        private lateinit var locale: Locale
 
-    @Test
-    fun zeroShouldBeFormattedAsZero() {
-        val shortNumber = shortNumber(0)
-        Assert.assertEquals("0", shortNumber)
-    }
+        /**
+         * Ensure the Locale is ENGLISH so that tests against literal strings like
+         * "1.0M" later, even if the test host's locale is e.g. GERMAN which would
+         * normally report "1,0M".
+         */
+        @BeforeClass
+        @JvmStatic
+        fun beforeClass() {
+            locale = Locale.getDefault()
+            Locale.setDefault(Locale.ENGLISH)
+        }
 
-    @Test
-    fun negativeValueShouldBeFormattedToNegativeValue() {
-        val shortNumber = shortNumber(-1)
-        Assert.assertEquals("-1", shortNumber)
-    }
+        @AfterClass
+        @JvmStatic
+        fun afterClass() {
+            Locale.setDefault(locale)
+        }
 
-    @Test
-    fun positiveValueShouldBeFormattedToPositiveValue() {
-        val shortNumber = shortNumber(1)
-        Assert.assertEquals("1", shortNumber)
-    }
-
-    @Test
-    fun bigNumbersShouldBeShortened() {
-        var shortNumber = 1L
-        Assert.assertEquals("1", shortNumber(shortNumber))
-        for (i in shortLetters.indices) {
-            if (i == 0) {
-                continue
-            }
-            shortNumber = 1000.0.pow(i.toDouble()).toLong()
-            Assert.assertEquals("1.0" + shortLetters[i], shortNumber(shortNumber))
+        @Parameterized.Parameters(name = "formatNumber_{0}")
+        @JvmStatic
+        fun data(): Iterable<Any> {
+            return listOf(
+                arrayOf(0, "0"),
+                arrayOf(1, "1"),
+                arrayOf(-1, "-1"),
+                arrayOf(999, "999"),
+                arrayOf(1000, "1.0K"),
+                arrayOf(1500, "1.5K"),
+                arrayOf(-1500, "-1.5K"),
+                arrayOf(1000.0.pow(2).toLong(), "1.0M"),
+                arrayOf(1000.0.pow(3).toLong(), "1.0G"),
+                arrayOf(1000.0.pow(4).toLong(), "1.0T"),
+                arrayOf(1000.0.pow(5).toLong(), "1.0P"),
+                arrayOf(1000.0.pow(6).toLong(), "1.0E"),
+                arrayOf(3, "3"),
+                arrayOf(35, "35"),
+                arrayOf(350, "350"),
+                arrayOf(3500, "3.5K"),
+                arrayOf(-3500, "-3.5K"),
+                arrayOf(3500 * 1000, "3.5M"),
+                arrayOf(3500 * 1000.0.pow(2).toLong(), "3.5G"),
+                arrayOf(3500 * 1000.0.pow(3).toLong(), "3.5T"),
+                arrayOf(3500 * 1000.0.pow(4).toLong(), "3.5P"),
+                arrayOf(3500 * 1000.0.pow(5).toLong(), "3.5E")
+            )
         }
     }
 
     @Test
-    fun roundingForNegativeAndPositiveValuesShouldBeTheSame() {
-        var value = 3492
-        Assert.assertEquals("-3.5K", shortNumber(-value))
-        Assert.assertEquals("3.5K", shortNumber(value))
-        value = 1501
-        Assert.assertEquals("-1.5K", shortNumber(-value))
-        Assert.assertEquals("1.5K", shortNumber(value))
+    fun test() {
+        Assert.assertEquals(want, formatNumber(input, 1000))
     }
 }