BAEL-3204 (#8085)

* BAEL-3204 * BAEL-3204
2019-11-16 00:15:43 +01:00
parent 86c72ffd7b
commit 0bf12a690c
7 changed files with 384 additions and 0 deletions
@@ -0,0 +1,40 @@
+package com.baeldung.simplelinearregression
+
+import org.junit.Assert.assertEquals
+import org.junit.jupiter.api.Test
+
+class SimpleLinearRegressionUnitTest {
+    @Test
+    fun givenAProperDataSetWhenFedToASimpleLinearRegressionModelThenItPredictsCorrectly() {
+        val xs = arrayListOf(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
+        val ys = arrayListOf(25, 35, 49, 60, 75, 90, 115, 130, 150, 200)
+
+        val model = SimpleLinearRegression(xs, ys)
+
+        val predictionOne = model.predict(2.5)
+        assertEquals(38.99, predictionOne, 0.01)
+
+        val predictionTwo = model.predict(7.5)
+        assertEquals(128.84, predictionTwo, 0.01)
+    }
+
+    @Test
+    fun givenAPredictableDataSetWhenCalculatingTheLossFunctionThenTheModelIsConsideredReliable() {
+        val xs = arrayListOf(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
+        val ys = arrayListOf(25, 35, 49, 60, 75, 90, 115, 130, 150, 200)
+
+        val model = SimpleLinearRegression(xs, ys)
+
+        assertEquals(0.95, model.calculateRSquared(), 0.01)
+    }
+
+    @Test
+    fun givenAnUnpredictableDataSetWhenCalculatingTheLossFunctionThenTheModelIsConsideredUnreliable() {
+        val xs = arrayListOf(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
+        val ys = arrayListOf(200, 0, 200, 0, 0, 0, -115, 1000, 0, 1)
+
+        val model = SimpleLinearRegression(xs, ys)
+
+        assertEquals(0.01, model.calculateRSquared(), 0.01)
+    }
+}