Updated DatabaseManager

Added a second constructor to make JUnit testing of the class feasible. Second constructor should not be used to create object in production code.

helpmehelpapplication/src/main/java/ntnu/sytemutvikling/team6/models/DatabaseManager.java

@@ -50,6 +50,38 @@ public DatabaseManager() {
         }
     }
 
+    /**
+     * Constructs a new {@code DatabaseManager} using database credentials
+     * <p>
+     *     Used primarily for JUnit tests. Production should use the constructor
+     *     using environment variables.
+     * </p>
+     *
+     * @param databaseURL the url to the database
+     * @param username the username used to log in to the database
+     * @param password the password used to log in to the database
+     * @throws IllegalArgumentException if databaseURL, username, or password is
+     *                                  {@code null} or blank
+     */
+
+    public DatabaseManager(String databaseURL, String username, String password) {
+        this.databaseURL = databaseURL;
+        this.username = username;
+        this.password = password;
+
+        if (this.databaseURL == null || this.databaseURL.isBlank()) {
+            throw new IllegalArgumentException("Database environment variable URL has not been set");
+        }
+
+        if (this.username == null || this.username.isBlank()) {
+            throw new IllegalArgumentException("Username environment variable has not been set");
+        }
+
+        if (this.password == null || this.password.isBlank()) {
+            throw new IllegalArgumentException("Password environment variable has not been set");
+        }
+    }
+
     /**
      * Creates the {@code charities} table if it does not already exist.
      * <p>
@@ -74,7 +106,7 @@ url VARCHAR(255),
             s.execute(sql_query);
         } catch (SQLException e) {
             e.printStackTrace();
-            throw new RuntimeException("Error creating tables.");
+            throw new RuntimeException("Error creating table.");
         }
     }
 
@@ -125,7 +157,7 @@ INSERT INTO charities (org_number, name, status, url, is_pre_approved)
 
 
              // Temporary table for parity check
-            sql_query = "CREATE TEMPORARY TABLE temp (org_number VARCHAR(100) PRIMARY KEY)";
+            sql_query = "CREATE TEMPORARY TABLE IF NOT EXISTS temp (org_number VARCHAR(100) PRIMARY KEY)";
                  try (PreparedStatement temp_create = conn.prepareStatement(sql_query)) {
                      temp_create.execute();
                  }