implement readFile storage method

src/main/java/Storage.java

@@ -1,6 +1,5 @@
-import java.io.BufferedWriter;
-import java.io.FileWriter;
-import java.io.IOException;
+import java.io.*;
+import java.util.Scanner;
 
 public class Storage implements StorageInterface {
     @Override
@@ -28,4 +27,24 @@ public class Storage implements StorageInterface {
         }
         return false;
     }
+
+    public String readFile(String path) {
+        if (!path.isEmpty()) {
+            StringBuilder data = new StringBuilder();
+            try {
+                File f = new File(path);
+                Scanner myReader = new Scanner(f);
+                while (myReader.hasNextLine()) {
+                    data.append(myReader.nextLine());
+                }
+                myReader.close();
+            } catch (FileNotFoundException e) {
+                e.printStackTrace();
+                return null;
+            }
+
+            return data.toString();
+        }
+        return null;
+    }
 }

src/test/java/StorageTest.java

@@ -47,4 +47,16 @@ class StorageTest {
         File f = new File(testFilePath);
         assertTrue(f.isFile());
     }
+
+    @Test
+    void readFile() {
+        String content = "test";
+
+        File f = new File(testFilePath);
+        if (!f.isFile()) {
+            assertTrue(storage.writeFile(testFilePath, content));
+        }
+
+        assertEquals(content, storage.readFile(testFilePath));
+    }
 }