handle duplicate approved account request

src/it/java/teammates/it/ui/webapi/RejectAccountRequestActionIT.java

@@ -222,7 +222,7 @@ protected void tearDown() {
         HibernateUtil.beginTransaction();
         List<AccountRequest> accountRequests = logic.getAllAccountRequests();
         for (AccountRequest ar : accountRequests) {
-            logic.deleteAccountRequest(ar.getEmail(), ar.getInstitute());
+            logic.deleteAccountRequest(ar.getId());
         }
         HibernateUtil.commitTransaction();
     }

src/it/java/teammates/it/ui/webapi/UpdateAccountRequestActionIT.java

@@ -227,6 +227,20 @@ public void testExecute() throws Exception {
         assertEquals(email, data.getEmail());
         assertEquals(institute, data.getInstitute());
         assertEquals(null, data.getComments());
+
+        ______TS("email with approved account request throws exception");
+        logic.createAccountRequestWithTransaction("test", "[email protected]",
+                "institute", AccountRequestStatus.APPROVED, "comments");
+        accountRequest = logic.createAccountRequestWithTransaction("test", "[email protected]",
+                "institute", AccountRequestStatus.PENDING, "comments");
+        requestBody = new AccountRequestUpdateRequest(accountRequest.getName(), accountRequest.getEmail(),
+                accountRequest.getInstitute(), AccountRequestStatus.APPROVED, comments);
+        params = new String[] {Const.ParamsNames.ACCOUNT_REQUEST_ID, accountRequest.getId().toString()};
+
+        ipe = verifyInvalidOperation(requestBody, params);
+
+        assertEquals(String.format("An account request with email %s has already been approved. "
+                + "Please reject or delete the account request instead.", accountRequest.getEmail()), ipe.getMessage());
     }
 
     @Override

src/main/java/teammates/sqllogic/api/Logic.java

@@ -204,6 +204,13 @@ public List<AccountRequest> getAllAccountRequests() {
         return accountRequestLogic.getAllAccountRequests();
     }
 
+    /**
+     * Get a list of account requests associated with email provided.
+     */
+    public List<AccountRequest> getApprovedAccountRequestsForEmailWithTransaction(String email) {
+        return accountRequestLogic.getApprovedAccountRequestsForEmailWithTransaction(email);
+    }
+
     /**
      * Gets an account.
      */

src/main/java/teammates/sqllogic/core/AccountRequestsLogic.java

@@ -142,6 +142,16 @@ public List<AccountRequest> getAllAccountRequests() {
         return accountRequestDb.getAllAccountRequests();
     }
 
+    /**
+     * Get a list of account requests associated with email provided.
+     */
+    public List<AccountRequest> getApprovedAccountRequestsForEmailWithTransaction(String email) {
+        HibernateUtil.beginTransaction();
+        List<AccountRequest> accountRequests = accountRequestDb.getApprovedAccountRequestsForEmail(email);
+        HibernateUtil.commitTransaction();
+        return accountRequests;
+    }
+
     /**
      * Creates/resets the account request with the given id such that it is not registered.
      */

src/main/java/teammates/storage/sqlapi/AccountRequestsDb.java

@@ -103,6 +103,20 @@ public List<AccountRequest> getAllAccountRequests() {
         return query.getResultList();
     }
 
+    /**
+     * Get all Account Requests for a given {@code email}.
+     */
+    public List<AccountRequest> getApprovedAccountRequestsForEmail(String email) {
+        CriteriaBuilder cb = HibernateUtil.getCriteriaBuilder();
+        CriteriaQuery<AccountRequest> cr = cb.createQuery(AccountRequest.class);
+        Root<AccountRequest> root = cr.from(AccountRequest.class);
+        cr.select(root).where(cb.and(cb.equal(root.get("email"), email),
+                cb.equal(root.get("status"), AccountRequestStatus.APPROVED)));
+
+        TypedQuery<AccountRequest> query = HibernateUtil.createQuery(cr);
+        return query.getResultList();
+    }
+
     /**
      * Get AccountRequest by {@code registrationKey} from database.
      */

src/main/java/teammates/ui/webapi/UpdateAccountRequestAction.java

@@ -47,6 +47,13 @@ public JsonResult execute() throws InvalidOperationException, InvalidHttpRequest
                         accountRequest.getEmail()));
             }
 
+            if (sqlLogic.getApprovedAccountRequestsForEmailWithTransaction(accountRequest.getEmail()).size() > 0) {
+                throw new InvalidOperationException(String.format(
+                    "An account request with email %s has already been approved. "
+                        + "Please reject or delete the account request instead.",
+                        accountRequest.getEmail()));
+            }
+
             try {
                 // should not need to update other fields for an approval
                 accountRequest.setStatus(accountRequestUpdateRequest.getStatus());