diff --git a/tests/phpunit/CRM/Contribute/BAO/ContributionTest.php b/tests/phpunit/CRM/Contribute/BAO/ContributionTest.php
index 475288bd9462..30996877b24d 100644
--- a/tests/phpunit/CRM/Contribute/BAO/ContributionTest.php
+++ b/tests/phpunit/CRM/Contribute/BAO/ContributionTest.php
@@ -1273,4 +1273,87 @@ public function testcalculateTaxAfterChangeInFinancialTypeForLineItems() {
     $this->assertEquals($taxAmount, 0, 'Amount does not match.');
   }
 
+  /**
+   * test for function calculateTaxForChangeInFinancialType()
+   */
+  public function testcalculateTaxForChangeInFinancialType() {
+    list($contribution, $financialAccount) = $this->createContributionWithTax();
+    $params = $this->alterLineItemsAndOtherParams($contribution, 20, 300);
+    $totalAmount = 360;
+    $oldTaxAmounts = array('new_tax_amount' => 60);
+    $changeFTAmount = 110;
+    CRM_Contribute_BAO_Contribution::calculateTaxForChangeInFinancialType($params, $totalAmount, $oldTaxAmounts, $changeFTAmount);
+    $this->assertEquals($totalAmount, 350, 'Amount does not match.');
+    $this->assertEquals($changeFTAmount, 120, 'Amount does not match.');
+    $this->assertEquals($params['tax_amount'], 20, 'Amount does not match.');
+    $this->assertEquals($oldTaxAmounts['new_tax_amount'], 50, 'Amount does not match.');
+    $this->assertEquals($oldTaxAmounts['previous_tax_amount'], 10, 'Amount does not match.');
+    $params = $this->alterLineItemsAndOtherParams($contribution, 0, 300);
+    $totalAmount = 300;
+    $oldTaxAmounts = array('new_tax_amount' => NULL);
+    $changeFTAmount = 110;
+    CRM_Contribute_BAO_Contribution::calculateTaxForChangeInFinancialType($params, $totalAmount, $oldTaxAmounts, $changeFTAmount);
+    $this->assertEquals($totalAmount, 310, 'Amount does not match.');
+    $this->assertEquals($changeFTAmount, 100, 'Amount does not match.');
+    $this->assertEquals(CRM_Utils_Array::value('tax_amount', $params), NULL, 'Amount does not match.');
+    $this->assertEquals($oldTaxAmounts['new_tax_amount'], NULL, 'Amount does not match.');
+    $this->assertEquals(CRM_Utils_Array::value('previous_tax_amount', $oldTaxAmounts), NULL, 'Amount does not match.');
+    $financialType = $this->createFinancialType();
+    $contributionParams = array(
+      'contact_id' => $contribution['contact_id'],
+      'financial_type_id' => $financialType['id'],
+      'total_amount' => 100,
+      'contribution_status_id' => 1,
+    );
+    $contribution = CRM_Contribute_BAO_Contribution::add($contributionParams);
+    $params = $this->alterLineItemsAndOtherParams($contribution, 10, 300);
+    $totalAmount = 330;
+    $oldTaxAmounts = array('new_tax_amount' => 30);
+    $changeFTAmount = 100;
+    CRM_Contribute_BAO_Contribution::calculateTaxForChangeInFinancialType($params, $totalAmount, $oldTaxAmounts, $changeFTAmount);
+    $this->assertEquals($totalAmount, 320, 'Amount does not match.');
+    $this->assertEquals($changeFTAmount, 110, 'Amount does not match.');
+    $this->assertEquals($params['tax_amount'], 10, 'Amount does not match.');
+    $this->assertEquals($oldTaxAmounts['new_tax_amount'], 20, 'Amount does not match.');
+    $this->assertEquals($oldTaxAmounts['previous_tax_amount'], 0, 'Amount does not match.');
+  }
+
+  /**
+   * Alter Line Item array to calculate tax change and other contribution attributes.
+   *
+   * @param array $contribution
+   *    contribution array
+   * @param float $taxRate
+   *   tax rate of line item
+   * @param float $totalAmount
+   *   Contribution total amount
+   * @param float $taxAmount
+   *  Tax amount
+   *
+   * @return array
+   */
+  public function alterLineItemsAndOtherParams($contribution, $taxRate, $totalAmount, $taxAmount = NULL) {
+    if (is_array($contribution)) {
+      $contributionId = $contribution['id'];
+      $contribution = new CRM_Contribute_DAO_Contribution();
+      $contribution->id = $contributionId;
+      $contribution->find(TRUE);
+    }
+    $params = array(
+      'contribution' => $contribution,
+      'prevContribution' => $contribution,
+    );
+    $lineItems = CRM_Price_BAO_LineItem::getLineItemsByContributionID($contribution->id);
+    foreach ($lineItems as $id => $lineItem) {
+      $lineItems[$id]['tax_rate'] = $taxRate;
+      $lineItems[$id]['line_total'] = $totalAmount;
+      $lineItems[$id]['id'] = $id;
+    }
+    $params['line_item'][1] = $lineItems;
+    if (isset($taxAmount)) {
+      $params['tax_amount'] = $taxAmount;
+    }
+    return $params;
+  }
+
 }