Migrate `ProxyOutputStream` to the `main.client` module, add unit/fuzz tests to make sure it works

1 files changed, 90 insertions, 0 deletions

diff --git a/main/client/test/src/mill/main/client/ClientTests.java b/main/client/test/src/mill/main/client/ClientTests.java
index 5ae44d3f..f3fcf154 100644
--- a/main/client/test/src/mill/main/client/ClientTests.java
+++ b/main/client/test/src/mill/main/client/ClientTests.java
@@ -1,10 +1,14 @@
 package mill.main.client;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
 import org.junit.Test;
 
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
+import java.io.OutputStream;
+import java.util.*;
 
 public class ClientTests {
     @Test
@@ -57,5 +61,91 @@ public class ClientTests {
         assertEquals(i.available(), 0);
     }
 
+    public byte[] readSamples(String ...samples) throws Exception{
+        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        for(String sample: samples) {
+            byte[] bytes = java.nio.file.Files.readAllBytes(
+                java.nio.file.Paths.get(getClass().getResource(sample).getFile())
+            );
+            out.write(bytes);
+        }
+        return out.toByteArray();
+    }
+    @Test
+    public void tinyProxyInputOutputStream() throws Exception{
+        proxyInputOutputStreams(
+                Arrays.copyOf(readSamples("/bandung.jpg"), 30),
+                readSamples(),
+                10
+        );
+    }
+    @Test
+    public void leftProxyInputOutputStream() throws Exception{
+        proxyInputOutputStreams(
+                readSamples("/bandung.jpg", "/akanon.mid", "/gettysburg.txt", "/pip.tar.gz"),
+                readSamples(),
+                2950
+        );
+    }
+    @Test
+    public void rightProxyInputOutputStream() throws Exception{
+        proxyInputOutputStreams(
+                readSamples(),
+                readSamples("/bandung.jpg", "/akanon.mid", "/gettysburg.txt", "/pip.tar.gz"),
+                3000
+        );
+    }
+    @Test
+    public void mixedProxyInputOutputStream() throws Exception{
+        proxyInputOutputStreams(
+                readSamples("/bandung.jpg", "/gettysburg.txt"),
+                readSamples("/akanon.mid", "/pip.tar.gz"),
+                3050
+        );
+    }
+
+    /**
+     * Make sure that when we shove data through both ProxyOutputStreams in
+     * variously sized chunks, we get the exact same bytes back out from the
+     * ProxyStreamPumper.
+     */
+    public void proxyInputOutputStreams(byte[] samples1,
+                                        byte[] samples2,
+                                        int chunkMax) throws Exception{
+
+        ByteArrayOutputStream pipe = new ByteArrayOutputStream();
+        OutputStream src1 = new ProxyOutputStream(pipe, 1);
+        OutputStream src2 = new ProxyOutputStream(pipe, -1);
+
+        Random random = new Random(31337);
+
+        int i1 = 0;
+        int i2 = 0;
+        while(i1 < samples1.length || i2 < samples2.length){
+            int chunk = random.nextInt(chunkMax);
+            if (random.nextBoolean() && i1 < samples1.length){
+                src1.write(samples1, i1, Math.min(samples1.length-i1, chunk));
+                src1.flush();
+                i1 += chunk;
+            }else if (i2 < samples2.length){
+                src2.write(samples2, i2, Math.min(samples2.length-i2, chunk));
+                src2.flush();
+                i2 += chunk;
+            }
+        }
+
+        byte[] bytes = pipe.toByteArray();
+
+
+        ByteArrayOutputStream dest1 = new ByteArrayOutputStream();
+        ByteArrayOutputStream dest2 = new ByteArrayOutputStream();
+        ProxyStreamPumper pumper = new ProxyStreamPumper(
+                new ByteArrayInputStream(bytes),
+                dest1, dest2
+        );
+        pumper.run();
+        assertTrue(Arrays.equals(samples1, dest1.toByteArray()));
+        assertTrue(Arrays.equals(samples2, dest2.toByteArray()));
+    }
 
 }
\ No newline at end of file