updated interactive test, simplified and cleaned up entire codebase

Signed-off-by: Konstantin Läufer <laufer@cs.luc.edu>

Author: klaeufer

build.sbt

@@ -4,8 +4,7 @@ version := "0.2"
 
 libraryDependencies ++= Seq(
   "org.apache.commons" %  "commons-collections4" % "4.5.0",
-  "com.github.sbt.junit" % "jupiter-interface" % "0.15.1" % Test,
-  "net.jqwik"   % "jqwik"             % "1.9.3"  % Test
+  "com.github.sbt.junit" % "jupiter-interface" % "0.15.1" % Test
 )
 
 enablePlugins(JavaAppPackaging)

src/main/java/edu/luc/cs/consoleapp/MainLeaky.java

@@ -1,10 +1,10 @@
 package edu.luc.cs.consoleapp;
 
+import java.util.Iterator;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Queue;
 import java.util.Scanner;
-import java.util.stream.Stream;
 
 import org.apache.commons.collections4.queue.CircularFifoQueue;
 
@@ -39,29 +39,32 @@ public static void main(final String[] args) {
     }
 
     final var input = new Scanner(System.in).useDelimiter("(?U)[^\\p{Alpha}0-9']+");
-    final var result = new LeakyQueue(lastNWords).process(input.tokens());
+    final var result = new LeakyQueue(lastNWords, input).process();
 
     result.forEach(
-        value -> {
-          System.out.println(value);
-          // terminate on I/O error such as SIGPIPE
-          if (System.out.checkError()) {
-            System.exit(1);
-          }
-        });
+      value -> {
+        System.out.println(value);
+        // terminate on I/O error such as SIGPIPE
+        if (System.out.checkError()) {
+          System.exit(1);
+        }
+      });
   }
 
-  private static class LeakyQueue {
+  static class LeakyQueue {
 
     private final Queue<String> queue;
 
-    public LeakyQueue(final int capacity) {
-      queue = new CircularFifoQueue<String>(capacity);
+    private final Iterator<String> input;
+
+    public LeakyQueue(final int capacity, final Iterator<String> input) {
+      this.queue = new CircularFifoQueue<String>(capacity);
+      this.input = input;
     }
 
-    private List<Queue<String>> process(final Stream<String> input) {
-      final List<Queue<String>> result = new LinkedList<>();
-      input.forEach(
+    public List<Queue<String>> process() {
+      final var result = new LinkedList<Queue<String>>();
+      input.forEachRemaining(
         word -> {
           queue.add(word); // the oldest item automatically gets evicted
           final var snapshot = new LinkedList<>(queue);
@@ -70,8 +73,4 @@ private List<Queue<String>> process(final Stream<String> input) {
       return result;
     }
   }
-
-  public static int getLastNWords() {
-    return LAST_N_WORDS;
-  }
 }

src/main/java/edu/luc/cs/consoleapp/MainStream.java

@@ -1,9 +1,9 @@
 package edu.luc.cs.consoleapp;
 
-import org.apache.commons.collections4.queue.CircularFifoQueue;
-
 import java.util.Scanner;
 
+import org.apache.commons.collections4.queue.CircularFifoQueue;
+
 // see https://stackoverflow.com/questions/1963806/#21699069
 // why we're using this implementation instead of java.util.ArrayQueue!
 

src/main/java/edu/luc/cs/consoleapp/MainTestable.java

@@ -46,13 +46,4 @@ public static void main(final String[] args) {
 
     slidingQueue.process();
   }
-
-  public static int getLastNWords() {
-		return LAST_N_WORDS;
-	}
-
-	@Override
-  public String toString() {
-    return "MainTestable []";
-  }
 }

src/main/java/edu/luc/cs/consoleapp/OutputHandler.java

@@ -0,0 +1,10 @@
+package edu.luc.cs.consoleapp;
+
+import java.util.Queue;
+import java.util.function.Consumer;
+
+/**
+ * Observer for decoupling sliding window logic from routing updates. The consumer processes the
+ * output and returns void.
+ */
+interface OutputHandler extends Consumer<Queue<String>> {}

src/test/java/edu/luc/cs/consoleapp/TestMainLeaky.java

@@ -0,0 +1,33 @@
+package edu.luc.cs.consoleapp;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import java.util.List;
+import java.util.Queue;
+
+import org.apache.commons.collections4.queue.CircularFifoQueue;
+
+import org.junit.jupiter.api.Test;
+
+public class TestMainLeaky {
+
+  @Test
+  public void testSlidingWindowEmpty() {
+    final var input = List.<String>of().iterator();
+    final var sut = new MainLeaky.LeakyQueue(3, input);
+    final var result = sut.process();
+    assertTrue(result.isEmpty());
+  }
+
+  @Test
+  public void testSlidingWindowNonempty() {
+    final var input = List.of("asdf", "qwer", "oiui", "zxcv").iterator();
+    final var sut = new MainLeaky.LeakyQueue(3, input);
+    final var result = sut.process();
+    assertEquals(4, result.size());
+    assertEquals(List.of("asdf"), result.get(0));
+    assertEquals(List.of("asdf", "qwer"), result.get(1));
+    assertEquals(List.of("asdf", "qwer", "oiui"), result.get(2));
+    assertEquals(List.of("qwer", "oiui", "zxcv"), result.get(3));
+  }
+}

src/test/java/edu/luc/cs/consoleapp/TestMainNotDRY.java

@@ -0,0 +1,58 @@
+package edu.luc.cs.consoleapp;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import java.util.ArrayList;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Queue;
+
+import org.apache.commons.collections4.queue.CircularFifoQueue;
+
+import org.junit.jupiter.api.Test;
+
+public class TestMainNotDRY {
+
+  @Test
+  public void testSlidingWindowEmpty() {
+    final var input = List.<String>of().iterator();
+    final var output = new OutputToList();
+    final var queue = new CircularFifoQueue<String>(3);
+    input.forEachRemaining(
+      word -> {
+        queue.add(word); // the oldest item automatically gets evicted
+        output.accept(queue); // send updated queue to output handler
+      });
+    final var result = output.result;
+    assertTrue(result.isEmpty());
+  }
+
+  @Test
+  public void testSlidingWindowNonempty() {
+    final var input = List.of("asdf", "qwer", "oiui", "zxcv").iterator();
+    final var output = new OutputToList();
+    final var queue = new CircularFifoQueue<String>(3);
+    input.forEachRemaining(
+      word -> {
+        queue.add(word); // the oldest item automatically gets evicted
+        output.accept(queue); // send updated queue to output handler
+      });
+    final var result = output.result;
+    assertEquals(4, result.size());
+    assertEquals(List.of("asdf"), result.get(0));
+    assertEquals(List.of("asdf", "qwer"), result.get(1));
+    assertEquals(List.of("asdf", "qwer", "oiui"), result.get(2));
+    assertEquals(List.of("qwer", "oiui", "zxcv"), result.get(3));
+  }
+
+  private static class OutputToList implements OutputHandler {
+
+    final List<Queue<String>> result = new ArrayList<>();
+
+    @Override
+    public void accept(final Queue<String> value) {
+      final var snapshot = new LinkedList<>(value);
+      result.add(snapshot);
+    }
+  }
+}

src/test/java/edu/luc/cs/consoleapp/TestSlidingQueue.java

@@ -6,7 +6,6 @@
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Queue;
-import java.util.stream.Stream;
 
 import org.junit.jupiter.api.Test;