From f54d81e0e2d97798b928ba32f5edab5519622f28 Mon Sep 17 00:00:00 2001
From: Neil Fuller <nfuller@google.com>
Date: Tue, 10 Jun 2014 10:54:57 +0100
Subject: Tests for Runtime.*Memory()

The docs describe a condition we do not test for.
The freeMemory / totalMemory tests have been consolidated
into a single test and joined by an additional assertion for
maxMemory().

The test for freeMemory from OldRuntimeTest has been tidied
up and moved to RuntimeTest.

Bug: 15507122
Change-Id: I4343215fb7f6b441613e25d3844d67812f5b5e94
---
 .../harmony/tests/java/lang/RuntimeTest.java       | 36 ++++++++++++++--------
 1 file changed, 23 insertions(+), 13 deletions(-)

(limited to 'harmony-tests')

diff --git a/harmony-tests/src/test/java/org/apache/harmony/tests/java/lang/RuntimeTest.java b/harmony-tests/src/test/java/org/apache/harmony/tests/java/lang/RuntimeTest.java
index 08a4fa9..17f822d 100644
--- a/harmony-tests/src/test/java/org/apache/harmony/tests/java/lang/RuntimeTest.java
+++ b/harmony-tests/src/test/java/org/apache/harmony/tests/java/lang/RuntimeTest.java
@@ -19,6 +19,8 @@ package org.apache.harmony.tests.java.lang;
 
 import java.io.IOException;
 import java.io.InputStream;
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Vector;
 
 public class RuntimeTest extends junit.framework.TestCase {
@@ -82,14 +84,6 @@ public class RuntimeTest extends junit.framework.TestCase {
     }
 
     /**
-     * java.lang.Runtime#freeMemory()
-     */
-    public void test_freeMemory() {
-        // Test for method long java.lang.Runtime.freeMemory()
-        assertTrue("freeMemory returned nonsense value", r.freeMemory() > 0);
-    }
-
-    /**
      * java.lang.Runtime#gc()
      */
     public void test_gc() {
@@ -142,12 +136,28 @@ public class RuntimeTest extends junit.framework.TestCase {
     }
 
     /**
-     * java.lang.Runtime#totalMemory()
+     * java.lang.Runtime#freeMemory() / java.lang.Runtime#totalMemory() /
+     * java.lang.Runtime#maxMemory()
      */
-    public void test_totalMemory() {
-        // Test for method long java.lang.Runtime.totalMemory()
-        assertTrue("totalMemory returned nonsense value", r.totalMemory() >= r
-                .freeMemory());
+    public void test_memory() {
+        assertTrue("freeMemory <= 0", r.freeMemory() > 0);
+        assertTrue("totalMemory() < freeMemory()", r.totalMemory() >= r.freeMemory());
+        assertTrue("maxMemory() < totalMemory()", r.maxMemory() >= r.totalMemory());
+    }
+
+    public void test_freeMemory() {
+        // Heap might grow or do GC at any time, so we can't really test a lot. Hence we are just
+        // doing some basic sanity checks here.
+        long freeBefore = r.freeMemory();
+        List<byte[]> arrays = new ArrayList<byte[]>();
+        for (int i = 1; i < 10; i++) {
+            arrays.add(new byte[10000]);
+        }
+        long freeAfter =  r.freeMemory();
+
+        // If totalMemory() has grown/shrunk freeMemory() might have gone down or up, but the
+        // freeMemory is unlikely to stay the same.
+        assertTrue("free memory must change with allocations", freeAfter != freeBefore);
     }
 
     public RuntimeTest() {
-- 
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