error due to mContext object

I am running Android studio in my Linux machine Ubuntu 15.04. I faced the problem during the compilation The gradle compilation messages are:

Information:Gradle tasks [:app:assembleDebug, :app:assembleDebugAndroidTest]
:app:preBuild UP-TO-DATE
:app:preDebugBuild UP-TO-DATE
:app:checkDebugManifest
:app:preReleaseBuild UP-TO-DATE
:app:prepareComAndroidSupportAppcompatV72300Library UP-TO-DATE
:app:prepareComAndroidSupportSupportV42300Library UP-TO-DATE
:app:prepareDebugDependencies
:app:compileDebugAidl UP-TO-DATE
:app:compileDebugRenderscript UP-TO-DATE
:app:generateDebugBuildConfig UP-TO-DATE
:app:generateDebugAssets UP-TO-DATE
:app:mergeDebugAssets UP-TO-DATE
:app:generateDebugResValues UP-TO-DATE
:app:generateDebugResources UP-TO-DATE
:app:mergeDebugResources UP-TO-DATE
:app:processDebugManifest UP-TO-DATE
:app:processDebugResources UP-TO-DATE
:app:generateDebugSources UP-TO-DATE
:app:processDebugJavaRes UP-TO-DATE
:app:compileDebugJavaWithJavac
Note: Some input files use or override a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
:app:compileDebugNdk UP-TO-DATE
:app:compileDebugSources
:app:preDexDebug UP-TO-DATE
:app:dexDebug
Picked up JAVA_TOOL_OPTIONS: -javaagent:/usr/share/java/jayatanaag.jar 
:app:validateDebugSigning
:app:packageDebug
:app:zipalignDebug
:app:assembleDebug
:app:preDebugAndroidTestBuild UP-TO-DATE
:app:prepareDebugAndroidTestDependencies
:app:compileDebugAndroidTestAidl UP-TO-DATE
:app:processDebugAndroidTestManifest UP-TO-DATE
:app:compileDebugAndroidTestRenderscript UP-TO-DATE
:app:generateDebugAndroidTestBuildConfig UP-TO-DATE
:app:generateDebugAndroidTestAssets UP-TO-DATE
:app:mergeDebugAndroidTestAssets UP-TO-DATE
:app:generateDebugAndroidTestResValues UP-TO-DATE
:app:generateDebugAndroidTestResources UP-TO-DATE
:app:mergeDebugAndroidTestResources UP-TO-DATE
:app:processDebugAndroidTestResources UP-TO-DATE
:app:generateDebugAndroidTestSources UP-TO-DATE
:app:processDebugAndroidTestJavaRes UP-TO-DATE
:app:compileDebugAndroidTestJavaWithJavac
/home/devkrishna/AndroidStudioProjects/Sunshine/app/src/androidTest/java/com/example/android/sunshine/app/test/TestDb.java
Error:(19, 29) error: constructor WeatherDbHelper in class WeatherDbHelper cannot be applied to given types;
required: Context,String,CursorFactory,int
found: Context
reason: actual and formal argument lists differ in length
Error:(35, 36) error: constructor WeatherDbHelper in class WeatherDbHelper cannot be applied to given types;
required: Context,String,CursorFactory,int
found: Context
reason: actual and formal argument lists differ in length
Error:Execution failed for task  ':app:compileDebugAndroidTestJavaWithJavac'.
> Compilation failed; see the compiler error output for details.
Information:BUILD FAILED
Information:Total time: 33.089 secs
Information:3 errors
Information:0 warnings
Information:See complete output in console

Here is the code for the file TestDb.java. It produces an error inside TestCreateDb() method that extends androidTestCase in the line:

SQLiteDatabase db = new WeatherDbHelper(this.mContext).getWritableDatabase();

So, please watch this line throughly.

package com.example.android.sunshine.app.test;

import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.test.AndroidTestCase;
import android.util.Log;

import com.example.android.sunshine.app.data.WeatherContract.LocationEntry;
import com.example.android.sunshine.app.data.WeatherContract.WeatherEntry;
import com.example.android.sunshine.app.data.WeatherDbHelper;

public class TestDb extends AndroidTestCase {

public static final String LOG_TAG = TestDb.class.getSimpleName();

public void testCreateDb() throws Throwable {
    mContext.deleteDatabase(WeatherDbHelper.DATABASE_NAME);
    SQLiteDatabase db = new WeatherDbHelper(
            this.mContext).getWritableDatabase();
    assertEquals(true, db.isOpen());
    db.close();
}

public void testInsertReadDb() {

    // Test data we're going to insert into the DB to see if it works.
    String testLocationSetting = "99705";
    String testCityName = "North Pole";
    double testLatitude = 64.7488;
    double testLongitude = -147.353;

    // If there's an error in those massive SQL table creation Strings,
    // errors will be thrown here when you try to get a writable database.
    WeatherDbHelper dbHelper = new WeatherDbHelper(mContext);
    SQLiteDatabase db = dbHelper.getWritableDatabase();

    // Create a new map of values, where column names are the keys
    ContentValues values = new ContentValues();
    values.put(LocationEntry.COLUMN_LOCATION_SETTING, testLocationSetting);
    values.put(LocationEntry.COLUMN_CITY_NAME, testCityName);
    values.put(LocationEntry.COLUMN_COORD_LAT, testLatitude);
    values.put(LocationEntry.COLUMN_COORD_LONG, testLongitude);

    long locationRowId;
    locationRowId = db.insert(LocationEntry.TABLE_NAME, null, values);

    // Verify we got a row back.
    assertTrue(locationRowId != -1);
    Log.d(LOG_TAG, "New row id: " + locationRowId);

    // Data's inserted.  IN THEORY.  Now pull some out to stare at it and verify it made
    // the round trip.

    // Specify which columns you want.
    String[] columns = {
            LocationEntry._ID,
            LocationEntry.COLUMN_LOCATION_SETTING,
            LocationEntry.COLUMN_CITY_NAME,
            LocationEntry.COLUMN_COORD_LAT,
            LocationEntry.COLUMN_COORD_LONG
    };

    // A cursor is your primary interface to the query results.
    Cursor cursor = db.query(
            LocationEntry.TABLE_NAME,  // Table to Query
            columns,
            null, // Columns for the "where" clause
            null, // Values for the "where" clause
            null, // columns to group by
            null, // columns to filter by row groups
            null // sort order
    );

    // If possible, move to the first row of the query results.
    if (cursor.moveToFirst()) {
        // Get the value in each column by finding the appropriate column index.
        int locationIndex = cursor.getColumnIndex(LocationEntry.COLUMN_LOCATION_SETTING);
        String location = cursor.getString(locationIndex);

        int nameIndex = cursor.getColumnIndex((LocationEntry.COLUMN_CITY_NAME));
        String name = cursor.getString(nameIndex);

        int latIndex = cursor.getColumnIndex((LocationEntry.COLUMN_COORD_LAT));
        double latitude = cursor.getDouble(latIndex);

        int longIndex = cursor.getColumnIndex((LocationEntry.COLUMN_COORD_LONG));
        double longitude = cursor.getDouble(longIndex);

        // Hooray, data was returned!  Assert that it's the right data, and that the database
        // creation code is working as intended.
        // Then take a break.  We both know that wasn't easy.
        assertEquals(testCityName, name);
        assertEquals(testLocationSetting, location);
        assertEquals(testLatitude, latitude);
        assertEquals(testLongitude, longitude);

        // Fantastic.  Now that we have a location, add some weather!
    } else {
        // That's weird, it works on MY machine...
        fail("No values returned :(");
    }

    // Fantastic.  Now that we have a location, add some weather!
    ContentValues weatherValues = new ContentValues();
    weatherValues.put(WeatherEntry.COLUMN_LOC_KEY, locationRowId);
    weatherValues.put(WeatherEntry.COLUMN_DATETEXT, "20141205");
    weatherValues.put(WeatherEntry.COLUMN_DEGREES, 1.1);
    weatherValues.put(WeatherEntry.COLUMN_HUMIDITY, 1.2);
    weatherValues.put(WeatherEntry.COLUMN_PRESSURE, 1.3);
    weatherValues.put(WeatherEntry.COLUMN_MAX_TEMP, 75);
    weatherValues.put(WeatherEntry.COLUMN_MIN_TEMP, 65);
    weatherValues.put(WeatherEntry.COLUMN_SHORT_DESC, "Asteroids");
    weatherValues.put(WeatherEntry.COLUMN_WIND_SPEED, 5.5);
    weatherValues.put(WeatherEntry.COLUMN_WEATHER_ID, 321);

    dbHelper.close();
}

}