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Test Suites
VSC4 Overview

VSC4 Overview

VSC5 is now available and is able to test in two modes: XPG4 and UNIX 98.


  • The industry standard Commands & Utilities test suite, verifying the the operating system commands.
  • The most complete test suite coverage for ISO/IEC 9945-2 (POSIX.2) and XPG4 commands in the industry.
  • Over 10,000 tests
  • Test Coverage: XPG4, ISO/IEC 9945-2:1993 (technically identical to IEEE Std POSIX® 1003.2-1992), FIPS 189
  • Mandatory for testing XPG4 Base 95 and the Single UNIX® Specification.
  • Also available , for UNIX 98 branding VSC5 , see our test suite matrix web page for more information.


The X/Open Commands Test Suite Release 4, known as VSC4, has the following test modes:

  • IEEE Std POSIX 1003.2-1992 (also known as ISO/IEC 9945-2)
  • X/Open Portability Guide Issue 4 (XPG4)

In the POSIX mode VSC4 can be run as a ISO/IEC 9945-2 Conformance Test Suite and is the recognised certification test tool in Europe. For X/Open branding the test suite is run in the X/Open mode (XPG4) which is essentially a superset of the POSIX test mode.

VSC4 uses the industry standard Test Environment Toolkit (TET) as its test harness. The TET is described elsewhere.

Disk Space Requirements

Disk space requirements on a typical CISC based system are as follows:

  • Source code - 40 Mbytes
  • Source and tests built - 60 Mbytes (on a CISC system)

Numbers of tests, and time to run

  • POSIX.2-1992 mode - over 6000 tests
  • XPG4 Mode - over 10,000 tests

A typical test run from start to finish takes approximately 20 hours on an Intel Pentium based system.

Test Coverage

The VSC test suite verifies the compliance of systems to the X/Open Commands & Utilities specification , a superset of the POSIX Shell & Utilities standard.

VSC features include:

  • The industry's first tests for the POSIX 1003.2 and XPG4 commands set. Standardisation of the commands is key to the development of portable shell applications.
  • Extensive automated tests for interactive commands, ensuring more rigorous testing that could be obtained by manual testing.

Test Organisation

The source tree and the executable tree are organised in a hierarchical design, being divided into sections corresponding to boundaries between various standards and parts contained therein.

Modular Design

VSC4 is modular, both at the implementation level and at the user level. The testing process is divided into clear stages -

Each stage is clearly documented in the VSC User and Installation Guide, which accompanies the product.


This stage includes setting up user-ids and groups for testing, and reading the tape. This stage includes configuring and installing the TET harness, which is used to control building, execution and cleanup of VSC tests.

Configuration and Installation

VSC provides a configuration script that interrogates the user and the system, checking for availability of certain resources.

After configuration, the installation stage builds the test harness and associated libraries.

Test Building

VSC separates the building of the test harness and tools from the testsets themselves. Since most of VSC is shell scripts, building the tests is simply a matter of linking them to the file to be executed (use of a link rather than a copy saves significant disk space). The test suite may be built completely or in sub-sections, which decrease in granularity from test sections and areas down to individual testsets.

Test Execution

Once built, the test suite may be run as a whole in one pass, or in sub-sections which decrease in granularity from test areas down to individual tests within testsets. If you are producing an X/Open branding application the test suite must run in a single uninterrupted pass.

Test Reporting

VSC generates an intermediate level journal file in a TET compliant format. This is sufficient for debugging purposes. When a formal report is required, such as for X/Open branding then the formal report writers provided with VSC are used to process the journal file.

Further Information




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