Parametrize all Reader tests

Author: silvanocerza

src/main/java/com/maxmind/db/BufferHolder.java

@@ -15,12 +15,16 @@ final class BufferHolder {
     private final Buffer buffer;
 
     BufferHolder(File database, FileMode mode) throws IOException {
+        this(database, mode, MultiBuffer.DEFAULT_CHUNK_SIZE);
+    }
+
+    BufferHolder(File database, FileMode mode, int chunkSize) throws IOException {
         try (RandomAccessFile file = new RandomAccessFile(database, "r");
              FileChannel channel = file.getChannel()) {
             long size = channel.size();
             if (mode == FileMode.MEMORY) {
                 Buffer buf;
-                if (size <= MultiBuffer.DEFAULT_CHUNK_SIZE) {
+                if (size <= chunkSize) {
                     buf = new SingleBuffer(size);
                 } else {
                     buf = new MultiBuffer(size);
@@ -32,7 +36,7 @@ final class BufferHolder {
                 }
                 this.buffer = buf;
             } else {
-                if (size <= MultiBuffer.DEFAULT_CHUNK_SIZE) {
+                if (size <= chunkSize) {
                     this.buffer = SingleBuffer.mapFromChannel(channel);
                 } else {
                     this.buffer = MultiBuffer.mapFromChannel(channel);

src/main/java/com/maxmind/db/Reader.java

@@ -56,6 +56,14 @@ public Reader(File database) throws IOException {
         this(database, NoCache.getInstance());
     }
 
+    Reader(File database, int chunkSize) throws IOException {
+        this(
+            new BufferHolder(database, FileMode.MEMORY_MAPPED, chunkSize),
+            database.getName(),
+            NoCache.getInstance()
+        );
+    }
+
     /**
      * Constructs a Reader for the MaxMind DB format, with the specified backing
      * cache. The file passed to it must be a valid MaxMind DB file such as a
@@ -69,6 +77,14 @@ public Reader(File database, NodeCache cache) throws IOException {
         this(database, FileMode.MEMORY_MAPPED, cache);
     }
 
+    Reader(File database, NodeCache cache, int chunkSize) throws IOException {
+        this(
+            new BufferHolder(database, FileMode.MEMORY_MAPPED, chunkSize),
+            database.getName(),
+            cache
+        );
+    }
+
     /**
      * Constructs a Reader with no caching, as if in mode
      * {@link FileMode#MEMORY}, without using a <code>File</code> instance.