Query-based Test Generation for Database Applications

David Chays, Adelphi UniversityJohn Shahid, Polytechnic University

Phyllis G. Frankl, Polytechnic University

DBTest '08, Vancouver, BC

Outline

• Issues in Testing DB Applications• AGENDA Overview• Generating Test Generation Queries• Conclusions and Future Work

Relational databases

• Data is viewed as a collection of relations– relation schema– relation (relation state)

Table E ssn name

001-00-0356 Johnson012-34-5678 Smith036-54-5555 Jones051-88-9911 Blake

• Tables, tuples, attributes, constraints for example, create table E (ssn char(11) primary key,

name char(25) not null)

DB Application• SQL: declarative language for defining and manipulating

databases. Includes statements to create and modify schema and to select, insert, delete, update table elements that satisfy certain conditions

• Application typically written in high level language host program with SQL statements embedded or dynamically generated

• SQL statements passed to DBMS for execution and results returned to host program

• Communication via host variables

Aspects of Correctness

• Does the DBMS perform all operations correctly?• Is concurrent access handled correctly?• Is the system fault-tolerant?• Is the system secure?• ...

Does the application program behave as intended?

Traditional vs. DB programs

• function• imperative nature• function• Semi-declarative nature

input

output

input DB state

output DB state

DB Application Testing Goal

• Select “interesting” DB states along with user inputs that exercise “interesting” behavior

• Cover wide variety of situations that could arise in practice

• Do so in a way that facilitates checking of output to user and resulting DB state

Current Practice

• Testing is largely manual• Limited tool support

– Database state generation– DBUnit – extension of JUnit with support for importing

XML descriptions of database state and for checking results of individual tests supplied by tester

• AGENDA goal: More thorough automation of entire test process for DB applications

AGENDA Parser

State Generator Input Generator

State Validator Output Validator

AGENDA DB

AGENDA System Overview• Inputs

• database schema• application source code• Sample values, divided into data groups• test heuristics• info about expected behavior of test cases• Constraints on expected database state and outputs

• Outputs• Initial database state• Test cases• Hooks for validation of resulting DB state and output• Error reports when tests violate constraints

AGENDA System Overview• Inputs

• database schema• application source code• Sample values, divided into data groups• test heuristics• info about expected behavior of test cases• Constraints on expected database state and outputs

• Outputs• Initial database state• Test cases• Hooks for validation of resulting DB state and output• Error reports when tests violate constraints

Student Registration Application Tables:

Person (id, name, passwd, type) Class (crsCode, credit, enrollment,

maxEnrollment, profId) Transcript (sid, code, grade)

who’s registered for what and their grades

Constraints in schema: primary keys (possibly composite) foreign key

Transcript.sid references Person.id Transcript.code references Class.crsCode

Sample data values and groups

Name:

DengDavidPhyllisGlebEricWang

Id:

--choice_name: Student112252334121013311------choice_name: Faculty888887

CrsCode:

--choice_name: UndergradCS101EL101CS110------choice_name: GradEL501CS608CS912

Sample output of State Generator

Sid Code Grade

311 CS912

252 CS101 C

311 EL101 A

311 CS608

112 CS912 B

Id Name Passwd Type

311 Deng deng123 1

112 Eric eric123 1

887 Phyllis pf123 2

252 Wang w123 1

888 Gleb g12 2

Crscode Credit Enrollment MaxEnroll ProfId

CS912 4 2 60 887

CS608 3 1 50 887

EL101 3 1 120 888

CS905 5 0 30 888

CS101 3 1 60 888

Table Person

Table Class

Table Transcript

Input Generator• Each combination of data groups can serve as a

test template for test cases.• For each input parameter (input host variable) find info

about data groups for the associated attribute along with candidate values in the Agenda DB.

• Selection of arbitrary elements of data groups does not work– SELECT sid FROM transcript WHERE code = :hv1 and grade = :hv2– Choosing hv1 = CS912, hv2 = ‘A’ leads to no rows that

satisfy the where clause– OK for testing robustness, but one also wants test cases

that test more typical behavior

• Original approach: Combination of sample values from relevant data groups + automatic generation and execution of SELECT statements to extract related attribute values

• New approach: more general, flexible, hopefully more effective

Sample Code (Class Registration)BEGIN DECLARE SECTION;1) int enroll, maxenroll ;2) char sid[20], code [10];END DECLARE SECTION;

void register(char[] sid, char[] code) {

3) EXEC SQL SELECT enrollment, maxEnrollment INTO :enroll, :maxEnroll FROM Class WHERE crsCode = :code

4) if (enroll < maxEnroll) {

5) EXEC SQL UPDATE Class SET enrollment = :enroll + 1 WHERE crsCode = :code ;

6) EXEC SQL INSERT INTO TRANSCRIPT (sid, code) VALUES (:sid, :code);

} // end if

7) COMMIT; } // end register transaction

Approach

• Test template– id: student– course code: undergrad

• General approach: generate a query to select values of these parameters that correspond to tuples in the populated DB representing these data groups

• Use auxiliary data:parameter_value_recs table

Table parameter_value_recsparameter_name group_name value

code Undergrad CS101

code Undergrad EL101

code Undergrad CS110

code Grad EL501

code Grad CS608

code Grad CS912

sid Student 112

sid Student 252

sid Student 334

sid Student 121

sid Student 013

sid Student 311

sid Faculty 888

sid Faculty 887

SELECT enrollment, maxEnrollment INTO :enroll, :maxEnroll

FROM Class WHERE crsCode = :code

SELECT

SELECT enrollment, maxEnrollment INTO :enroll, :maxEnroll

FROM Class WHERE crsCode = :code

SELECT temp1

SELECT enrollment, maxEnrollment INTO :enroll, :maxEnroll

FROM Class WHERE crsCode = :code

SELECT temp1 FROM (

SELECT enrollment, maxEnrollment INTO :enroll, :maxEnroll

FROM Class WHERE crsCode = :code

SELECT temp1 FROM ((SELECT value AS temp1 FROM parameter_value_recs WHERE parameter_name = ‘:code’

AND group_name = ‘Undergrad’)

SELECT enrollment, maxEnrollment INTO :enroll, :maxEnroll

FROM Class WHERE crsCode = :code

SELECT temp1 FROM ((SELECT value AS temp1 FROM parameter_value_recs WHERE parameter_name = ‘:code’

AND group_name = ‘Undergrad’))WHERE EXISTS (

SELECT * FROM

SELECT enrollment, maxEnrollment INTO :enroll, :maxEnroll

FROM Class WHERE crsCode = :code

SELECT temp1 FROM ((SELECT value AS temp1 FROM parameter_value_recs WHERE parameter_name = ‘:code’

AND group_name = ‘Undergrad’))WHERE EXISTS (

SELECT * FROM Class

SELECT enrollment, maxEnrollment INTO :enroll, :maxEnroll

FROM Class WHERE crsCode = :code

SELECT temp1 FROM ((SELECT value AS temp1 FROM parameter_value_recs WHERE parameter_name = ‘:code’

AND group_name = ‘Undergrad’))WHERE EXISTS (

SELECT * FROM ClassWHERE crsCode = temp1

)

SELECT enrollment, maxEnrollment INTO :enroll, :maxEnroll

FROM Class WHERE crsCode = :code

SELECT temp1 FROM ((SELECT value AS temp1 FROM parameter_value_recs WHERE parameter_name = ‘:code’

AND group_name = ‘Undergrad’))WHERE EXISTS (

SELECT * FROM ClassWHERE crsCode = temp1

)

UPDATE Class SET enrollment = :enroll + 1 WHERE crsCode = :code

SELECT temp1 FROM ((SELECT value AS temp1 FROM parameter_value_recs WHERE parameter_name = ‘:code’

AND group_name = ‘Undergrad’))WHERE EXISTS (

SELECT * FROM ClassWHERE crsCode = temp1

)

INSERT INTO Transcript (sid, code) VALUES (:sid, :code)

SELECT

INSERT INTO Transcript (sid, code) VALUES (:sid, :code)

SELECT temp1, temp2

INSERT INTO Transcript (sid, code) VALUES (:sid, :code)

SELECT temp1, temp2 FROM (

INSERT INTO Transcript (sid, code) VALUES (:sid, :code)

SELECT temp1, temp2 FROM ((SELECT value AS temp1 FROM parameter_value_recs WHERE parameter_name = ‘:sid’ AND

group_name = ‘Student’)

INSERT INTO Transcript (sid, code) VALUES (:sid, :code)

SELECT temp1, temp2 FROM ((SELECT value AS temp1 FROM parameter_value_recs WHERE parameter_name = ‘:sid’ AND group_name = ‘Student’)CROSS_JOIN(SELECT value AS temp2 FROM parameter_value_recs WHERE parameter_name = ‘:code’ AND group_name = ‘Undergrad’)

INSERT INTO Transcript (sid, code) VALUES (:sid, :code)

SELECT temp1, temp2 FROM ((SELECT value AS temp1 FROM parameter_value_recs WHERE parameter_name = ‘:sid’ AND

group_name = ‘Student’)CROSS_JOIN(SELECT value AS temp2 FROM parameter_value_recs WHERE parameter_name = ‘:code’ AND

group_name = ‘Undergrad’))WHERE NOT EXISTS (SELECT sid, code FROM Transcript

WHERE sid = temp1 and code = temp2)

INSERT INTO Transcript (sid, code) VALUES (:sid, :code)

SELECT temp1, temp2 FROM ((SELECT value AS temp1 FROM parameter_value_recs WHERE parameter_name = ‘:sid’ AND group_name = ‘Student’)CROSS_JOIN(SELECT value AS temp2 FROM parameter_value_recs WHERE parameter_name = ‘:code’ AND group_name = ‘Undergrad’)

)WHERE NOT EXISTS (SELECT sid, code FROM Transcript

WHERE sid = temp1 and code = temp2)ANDEXISTS (SELECT id FROM Person WHERE id = temp1)

INSERT INTO Transcript (sid, code) VALUES (:sid, :code)

SELECT temp1, temp2 FROM ((SELECT value AS temp1 FROM parameter_value_recs WHERE parameter_name = ‘:sid’ AND group_name = ‘Student’)CROSS_JOIN(SELECT value AS temp2 FROM parameter_value_recs WHERE parameter_name = ‘:code’ AND group_name = ‘Undergrad’)

)WHERE NOT EXISTS (SELECT sid, code FROM Transcript

WHERE sid = temp1 and code = temp2)ANDEXISTS (SELECT id FROM Person WHERE id = temp1)ANDEXISTS (SELECT crsCode FROM Class WHERE crsCode = temp2)

INSERT INTO Transcript (sid, code) VALUES (:sid, :code)

SELECT temp1, temp2 FROM ((SELECT value AS temp1 FROM parameter_value_recs WHERE parameter_name = ‘:sid’ AND group_name = ‘Student’)CROSS_JOIN(SELECT value AS temp2 FROM parameter_value_recs WHERE parameter_name = ‘:code’ AND group_name = ‘Undergrad’)

)W HERE NOT EXISTS (SELECT sid, code FROM Transcript

WHERE sid = temp1 and code = temp2)ANDEXISTS (SELECT id FROM Person WHERE id = temp1)ANDEXISTS (SELECT crsCode FROM Class WHERE crsCode = temp2)

What is the result?

Sid Code Grade

311 CS912

252 CS101 C

311 EL101 A

311 CS608

112 CS912 B

Id Name Passwd Type

311 Deng deng123 1

112 Eric eric123 1

887 Phyllis pf123 2

252 Wang w123 1

888 Gleb g12 2

Crscode Credit Enrollment MaxEnroll ProfId

CS912 4 2 60 887

CS608 3 1 50 887

EL101 3 1 120 888

CS905 5 0 30 888

CS101 3 1 60 888

Table Person

Table Class

Table Transcript

Test Cases

(112, CS101)(112, EL101)(252, EL101)(311, CS101)

Status of Test Generation Query Generator

• Implemented– Automatically generates test generation queries

given info about application unit’s SQL statements and parameters

• Parsing application for useful test information– Working on automating this for Java programs

Initial evaluation

• 5 transactions of TPC-C Benchmark• Produced Type A test cases that caused all 5

transactions to commit• Current work: How effective are these tests?

– Seeded faults in the transactions– If transaction commits, check specification violation– If transaction does not commit, this means the test case

was not Type A or there was a bug

• Initial results on error-seeded versions– Some transactions identified as buggy but most committed

with no specification violation

Conclusions

• Interplay between input parameters and DB state, and SQL statements under test

• Integration, flexibility– Test template– Type A inputs

• Non-empty result sets • Honoring constraints in updates

Ongoing and Future Work• Improve State Generator• Experiment

– Evaluate effectiveness and performance

• Complex manipulation of host variables by host program– Symbolic execution

• Type A and type B test cases • Other kinds of test templates• Further automate and integrate Java

static analysis tools

Related Work

• Willmor and Embury, “An intensional approach to the specification of test cases for database applications”, ICSE 2006

• Binnig et al, “Reverse query processing”, ICDE 2007

• Binnig et al, “Qagen: generating query-aware test databases”, ACM SIGMOD 2007.

• Emmi et al, “Dynamic test input generation for database applications”, ISSTA 2007.

Previous work on AGENDA• “A Framework for Testing Database Applications”,

ISSTA 2000• Earlier version of AGENDA System was demonstrated

at ASE03/ICSE03• “An AGENDA for testing relational database

applications”, Journal of Software Testing, Verification and Reliability, Mar 2004.

• “Testing Database Transaction Concurrency”, International Conference on Automated Software Engineering 2003

• “Testing Web Database Applications”, TAV-WEB workshop, ACM SIGSOFT Notes, Sept 2004

• “Testing Database Transaction with AGENDA”, International Conference on Software Engineering 2005

Questions?

chays@adelphi.edu