Patent Publication Number: US-2023140267-A1

Title: Code coverage measurement for test systems

Description:
BACKGROUND 
     The present invention relates to code coverage measurement, and more specifically, to code coverage measurement for test systems. 
     Test completeness is traditionally measured by using code coverage. Code coverage is a measure used to describe the degree to which the source code of a program is executed when a particular test suite runs. 
     A program with high test coverage has had more of its source code executed during testing. A high test coverage for a program suggests that there is a lower chance of the program containing undetected software bugs compared to a program with low test coverage. Many different metrics can be used to calculate test coverage; some of the most basic are the percentage of program subroutines and the percentage of program statements called during execution of the test suite. 
     Code coverage is typically done by instrumenting at a low level such as the machine instructions. This is reported at the module level and then aggregated up to a total value. Existing solutions focus on whether a code path has been executed, or whether it has been executed for certain external input criteria. 
     In reality, the problem is much more complex as the execution will depend on the values passed to various modules. These can lead to a large number of error flows which are not fully captured by the code coverage metric. For example, if a module performed various input validation and branched to code which set a bad return code and returned for each of these checks, it may be that only a small percentage of the code would be concerned with the return code setting and returning. Therefore, the module could have a very high coverage, but not necessarily actually have tested many of the possible error flows. This would have to be determined by looking at line by line coverage data. 
     SUMMARY 
     According to an aspect of the present invention there is provided a computer-implemented method for code coverage for test systems for testing source code, comprising: obtaining trace records written at entry and exit to one or more test modules for function calls to the test modules; comparing response codes for the functions extracted from the trace with a finite list of response codes retrieved from metadata for the source code for the functions; and analyzing a code coverage based on the comparison. 
     According to another aspect of the present invention there is provided a system for code coverage for test systems for testing source code, comprising: a processor and a memory configured to provide computer program instructions to the processor to execute the function of the components: a trace obtaining component for obtaining trace records written at entry and exit to one or more test modules for function calls to the test modules; a metadata comparing component for comparing response codes for the functions extracted from the trace with a finite list of response codes retrieved from metadata for the source code for the functions; and a code coverage analyzing component for analyzing a code coverage based on the comparison. 
     According to a further aspect of the present invention there is provided a computer program product for code coverage for test systems for testing source code, the computer program product comprising a computer readable storage medium having program instructions embodied therewith, the program instructions executable by a processor to cause the processor to: obtain trace records written at entry and exit to one or more test modules for function calls to the test modules; compare response codes for the functions extracted from the trace with a finite list of response codes retrieved from metadata for the source code for the functions; and analyze a code coverage based on the comparison. 
     The computer readable storage medium may be a non-transitory computer readable storage medium and the computer readable program code may be executable by a processing circuit. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, both as to organization and method of operation, together with objects, features, and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanying drawings. 
       Preferred embodiments of the present invention will now be described, by way of example only, with reference to the following drawings in which: 
         FIG.  1    is a schematic diagram of a method in accordance with the present invention; 
         FIG.  2    is a flow diagram of an example embodiment of a method in accordance with the present invention; 
         FIG.  3    is block diagram of an example embodiment of a system in accordance with the present invention; 
         FIG.  4    is a block diagram of an embodiment of a computer system or cloud server in which the present invention may be implemented; 
         FIG.  5    is a schematic diagram of a cloud computing environment in which the present invention may be implemented; and 
         FIG.  6    is a diagram of abstraction model layers of a cloud computing environment in which the present invention may be implemented. 
     
    
    
     It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numbers may be repeated among the figures to indicate corresponding or analogous features. 
     DETAILED DESCRIPTION 
     A method and system are provided for analyzing code coverage during testing by using trace data based on input and output combinations rather than code path. 
     The source code may be tested by test modules and their inputs and outputs are traced. The inputs may include the functions that the test module has been called for and other possible inputs. Other possible inputs may include numerical values required by a function, for example, how much storage to allocate, or they may include other input parameters that a function may require. The outputs may include response codes that indicate that either the call is successful or the reason for the call failing. Each test module may call other test modules and therefore a trace has a form where each input trace is linked to an output trace. 
     The term “function” is used to describe a function or method that may be executed by being called and includes, as examples, an application programming interface (API) call, a Java method (Java is a trade mark of Oracle Corporation), or an IBM Customer Information Control System (CICS) function (IBM CICS is a trade mark of International Business Machines Corporation). 
     Metadata listing the inputs and outputs is retrieved for the functions being input. This includes the values of data items for function codes and response codes, which are a finite set. The metadata may be, for example, a documented list of functions for the source code, or may be obtained by a scan of the source code. Inputs have the potential to affect the code path of execution within a program; therefore, inputs are required in addition to the outputs. 
     The described method and system compare the trace response data to the metadata for functions executed by the test module to determine the coverage achieved by the test module. 
     Referring to  FIG.  1   , a schematic diagram  100  illustrates the described method and system. As part of a test system, inputs  110  are made in the form of function inputs  111  and other inputs  112  (for example, function parameters or values) to a test module  120  and outputs  130  are returned in the form of response codes such as return codes  131  and reason codes  132 . The test module  120  may be an executable module to test calls of the source code. A test module  120  may call other test modules  120  as part of its execution and the outputs  130  may be from the resultant series of test modules  120 . 
     Metadata codes  140  are provided as a finite list of all response codes, such as in the form of return codes and reason codes for functions. Return codes  131  may indicate a successful call and reason codes  132  may provide a reason for a failure of a call. 
     A code coverage system  150  as described herein receives trace data  151  of the inputs  110  and the outputs  130  for the functions executed by the one or more test modules  120 . The code coverage system  150  also retrieves metadata  152  relating to the inputs  110  and outputs  130  in the form of a finite list of possible response codes for the functions executed by the test module(s)  120 . The code coverage system  150  analyzes the coverage  153  of the test module(s)  120  by comparing the trace data  151  and the retrieved metadata codes  152 . 
     Referring to  FIG.  2   , a flow diagram  200  shows an example embodiment of the described method of analyzing code coverage of source code in a test system. 
     The method may obtain  201  trace records written at entry and exit to one or more test modules for function calls to the test modules. This may include running a test to produce a trace with trace records written at entry and exit for the functions being executed. When a trace is run, it captures all input and output function calls for each test module. This may include collecting an input trace of modules for functions that the test modules have called and collecting an output trace of test modules including response codes of functions. The response codes may include successful return codes and reason codes for failed calls. 
     The entry and exit trace records are paired up  202  to produce a single record. Inputs to a function are provided by the entry trace record and outputs from the function are provided by an exit trace record and pairing the entry and exit trace records provides information about the code paths executed. 
     Response codes are extracted for the executed functions  203  and may be sorted including removing duplicates. A record may be created for each function using the input and output trace of each module with a list of the response codes found. 
     The method may retrieve  204  metadata codes of all response codes for each function in each test module that have been executed in the test. The method may compare  205  the record of trace records with the metadata codes for the functions to determine coverage. 
     The coverage of the functions is analyzed  206 . The codes may be grouped  207  into multiple levels and comparison data from each level may be aggregated into the higher level. 
     In one embodiment, looking at a specific function and taking the simplest case of the combinations of function calls and response codes, the levels may be aggregated as follows. The coverage of a function may be determined as the percentage of possible response codes that appear in the trace compared with metadata of the finite list of the responses that the function can return. The coverage of a module may be determined in the same way but looking at all possible functions and all possible response codes for each function. The coverage of the total code may further be determined in the same way but looking at all possible modules, with all possible functions and all possible response codes. 
     In another embodiment, code may be grouped into multiple levels: for example, classes, methods, and functions. Data from each level may be aggregated into the higher level. 
     Missing code paths (i.e. functions or response codes) that are listed in the definitive list of metadata codes but are not recorded in the trace codes may be analyzed  208  to provide feedback about missing tests that may be required to be performed. 
     At a basic level, the method may look at functions and the response codes from them. For example, a function may be READ or WRITE and responses may be OK, NOTFOUND, NOTAUTH, etc. This may be extended to include input and output values to the function and response codes. For example, the input values and output values may include options on the READ such as EXCLUSIVE with options YES or NO, to indicate the READ must get exclusive access to something. 
     An example is provided to illustrate the described method. Trace records are written at entry for a function, where a function may be a function, a method, or an API call. Trace records are written at exit for a function and a response code, where response codes may be in the form of one or more of return codes, reason codes, and exceptions. Metadata is retrieved that lists all functions with response codes. The functions may describe their place in a hierarchy with higher levels in the source code. 
     The following general terminology is used for trace records: 
     Entry: Function; and 
     Exit: Function; response code. 
     For an example of an application programming interface (API), the metadata may be a documented list of functions and the trace records may be of the form: 
     Entry: API name; 
     Exit: API name, return code. 
     For an example in IBM CICS, the metadata may be the API description, CDURUN, and the trace records may be of the form: 
     Entry: Domain, gate, function; 
     Exit: Domain, gate, function, return code, response code. 
     For an example in Java, the metadata may be a Javadoc or a scan of code and the trace records may be of the form: 
     Entry: API name; 
     Exit: API name, return code. 
     IBM CICS terminology is used in the following example. The hierarchy of levels in the source code are provided by Domain/Gate/Function and the metadata is the list of CDURUNs and their contents. 
     In this example, the gate “Business Application Container” (BACR) of the domain of “Business Application” (BA) is tested. 
     Example trace data may be obtained as follows: 
     BA/BACR/DELETE_CONTAINER/OK 
     BA/BACR/DELETE_CONTAINER/CONTAINER_NOT_FOUND 
     BA/BACR/GET_CONTAINER_INTO/OK 
     BA/BACR/GET_CONTAINER_SET/OK 
     BA/BACR/PUT_CONTAINER/OK 
     BA/BACR/PUT_CONTAINER/INVALID_CONTAINER_NAME 
     BA/BACR/COPY_CONTAINER/OK 
     The finite list of metadata codes for the functions of the gate BACR is as follows: 
     BA/BACR/DELETE_CONTAINER/OK 
     BA/BACR/DELETE_CONTAINER/CONTAINER_NOT_FOUND 
     BA/BACR/DELETE_CONTAINER/CONTAINER_READONLY 
     BA/BACR/DELETE_CONTAINER/INVALID_CONTAINER_NAME 
     BA/BACR/GET_CONTAINER_INTO/OK 
     BA/BACR/GET_CONTAINER_INTO/CONTAINER_NOT_FOUND 
     BA/BACR/GET_CONTAINER_SET/OK 
     BA/BACR/GET_CONTAINER_SET/CONTAINER_NOT_FOUND 
     BA/BACR/PUT_CONTAINER/OK 
     BA/BACR/PUT_CONTAINER/INVALID_CONTAINER_NAME 
     BA/BACR/GET_CONTAINER_LENGTH/OK 
     BA/BACR/GET_CONTAINER_LENGTH/CONTAINER_NOT_FOUND 
     BA/BACR/MOVE_CONTAINER/OK 
     BA/BACR/MOVE_CONTAINER/CONTAINER_NOT_FOUND 
     BA/BACR/MOVE_CONTAINER/CONTAINER_READONLY 
     BA/BACR/COPY_CONTAINER/OK 
     BA/BACR/COPY_CONTAINER/CONTAINER_NOT_FOUND 
     BA/B ACR/COPY_CONTAINER/CONTAINER_READONLY 
     Comparing the trace data with the metadata has the following results with the trace codes shown in bold. 
     BA/BACR/DELETE_CONTAINER/OK 
     BA/BACR/DELETE_CONTAINER/CONTAINER_NOT_FOUND 
     BA/BACR/DELETE_CONTAINER/CONTAINER_READONLY 
     BA/BACR/DELETE_CONTAINER/INVALID_CONTAINER_NAME 
     BA/BACR/GET_CONTAINER_INTO/OK 
     BA/BACR/GET_CONTAINER_INTO/CONTAINER_NOT_FOUND 
     BA/BACR/GET_CONTAINER_SET/OK 
     BA/BACR/GET_CONTAINER_SET/CONTAINER_NOT_FOUND 
     BA/BACR/PUT_CONTAINER/OK 
     BA/BACR/PUT_CONTAINER/IN VALID_CONTAINER_NAME 
     BA/BACR/GET_CONTAINER_LENGTH/OK 
     BA/BACR/GET_CONTAINER_LENGTH/CONTAINER_NOT_FOUND 
     BA/BACR/MOVE_CONTAINER/OK 
     BA/BACR/MOVE_CONTAINER/CONTAINER_NOT_FOUND 
     BA/BACR/MOVE_CONTAINER/CONTAINER_READONLY 
     BA/BACR/COPY_CONTAINER/OK 
     BA/BACR/COPY_CONTAINER/CONTAINER_NOT_FOUND 
     BA/B ACR/COPY_CONTAINER/CONTAINER_READONLY 
     Coverage results at function level are therefore as follows: 
     
       
         
           
               
               
               
             
               
                   
               
             
            
               
                 BA/BACR/DELETE_CONTAINER 
                 2 covered out of 4 
                 50% 
               
               
                 BA/BACR/GET_CONTAINER_INTO 
                 1 covered out of 2 
                 50% 
               
               
                 BA/BACR/GET_CONTAINER_SET 
                 1 covered out of 2 
                 50% 
               
               
                 BA/BACR/PUT_CONTAINER 
                 2 covered out of 2 
                 100%  
               
               
                 BA/BACR/GET_CONTAINER_LENGTH 
                 0 covered out of 2 
                  0% 
               
               
                 BA/BACR/MOVE_CONTAINER 
                 0 covered out of 3 
                  0% 
               
               
                 BA/BACR/COPY_CONTAINER 
                 1 covered out of 3 
                 33% 
               
               
                   
               
            
           
         
       
     
     Coverage results may be aggregated at method level. In this case for gate BACR the coverage is: 
     BA/BACR7 covered out of 18 39% 
     Coverage results may be aggregated at class level. In this case for domain BA the coverage is: 
     
       
         
           
               
               
               
               
             
               
                   
                   
               
             
            
               
                   
                 BA 
                 27 covered out of 96 
                 28% 
               
               
                   
                   
               
            
           
         
       
     
     Coverage results may be aggregated at program level. In this case for the CICS code the coverage is: 
     
       
         
           
               
               
               
               
             
               
                   
                   
               
             
            
               
                   
                 CICS 
                 564 covered out of 7812 
                 7% 
               
               
                   
                   
               
            
           
         
       
     
     The described method and system use trace data to collect code coverage information. Trace data provides the actual path taken and not just an external view. This has the benefit that no tooling is required. As code coverage is determined from a trace, it does not require any instrumentation. 
     The code coverage used here is a measure of which functions have been executed and what possible outputs have been returned and it does not matter how long those paths are. This is better aligned to code and test complexity. 
     Referring to  FIG.  3   , a block diagram shows an example embodiment of the described code coverage system  150  provided at a computing system  300 . The computing system  300  or a separate computing system may also include a testing system  310  and a tracing system  320  that are run in conjunction with or incorporated with the code coverage system  150 . 
     The computing system  300  includes at least one processor  301 , a hardware module, or a circuit for executing the functions of the described components which may be software units executing on the at least one processor. Multiple processors running parallel processing threads may be provided enabling parallel processing of some or all of the functions of the components. Memory  302  may be configured to provide computer instructions  303  to the at least one processor  301  to carry out the functionality of the components. 
     The code coverage system  150  may include a trace obtaining component  331  for obtaining a trace with trace records written at entry and exit to one or more test modules for function calls to the test modules. The trace obtaining component  331  may obtain trace records where a test module calls another test module as part of its execution of a function call. 
     The trace obtaining component  331  may include a trace handling component  332  for pairing up entry and exit trace records to generate trace records, sorting the trace records, and removing duplicate trace records. 
     The code coverage system  150  may include a metadata retrieving component  333  for and a metadata for retrieving metadata for the source code for the functions and a metadata comparing component  334  for comparing response codes for the functions extracted from the trace with a finite list of response codes retrieved from metadata for the source code for the functions. The metadata comparing component  334  may provide a proportion of the metadata response codes provided in the trace records. 
     The code coverage system  150  may include a code coverage analyzing component  335  for analyzing a code coverage based on the comparison results of the metadata comparing component  334 . The code coverage analyzing component  335  may include a level aggregating component  336  for grouping the functions into higher levels and aggregating the code coverage for each level into higher level analysis. A higher level may be a module aggregating all possible functions and all possible response codes for each function. A further higher level may be a total source code aggregating all possible modules. Alternatively, a higher level may be a higher level of a function hierarchy. 
     The code coverage system  150  may include a missing test analysis component  337  for analyzing response codes of the metadata that are missing from the trace records to provide feedback relating to required tests. 
       FIG.  4    depicts a block diagram of components of a computing system  300  as used for the code coverage system  150 , in accordance with an embodiment of the present invention. It should be appreciated that  FIG.  4    provides only an illustration of one implementation and does not imply any limitations with regard to the environments in which different embodiments may be implemented. Many modifications to the depicted environment may be made. 
     The computing system can include one or more processors  402 , one or more computer-readable RAMs  404 , one or more computer-readable ROMs  406 , one or more computer readable storage media  408 , device drivers  412 , read/write drive or interface  414 , and network adapter or interface  416 , all interconnected over a communications fabric  418 . Communications fabric  418  can be implemented with any architecture designed for passing data and/or control information between processors (such as microprocessors, communications and network processors, etc.), system memory, peripheral devices, and any other hardware components within the system. 
     One or more operating systems  410 , and application programs  411 , such as the code coverage system  150  are stored on one or more of the computer readable storage media  408  for execution by one or more of the processors  402  via one or more of the respective RAMs  404  (which typically include cache memory). In the illustrated embodiment, each of the computer readable storage media  408  can be a magnetic disk storage device of an internal hard drive, CD-ROM, DVD, memory stick, magnetic tape, magnetic disk, optical disk, a semiconductor storage device such as RAM, ROM, EPROM, flash memory, or any other computer readable storage media that can store a computer program and digital information, in accordance with embodiments of the invention. 
     The computing system can also include a R/W drive or interface  414  to read from and write to one or more portable computer readable storage media  426 . Application programs  411  on the computing system can be stored on one or more of the portable computer readable storage media  426 , read via the respective R/W drive or interface  414  and loaded into the respective computer readable storage media  408 . 
     The computing system can also include a network adapter or interface  416 , such as a TCP/IP adapter card or wireless communication adapter. Application programs  411  on the computing system can be downloaded to the computing device from an external computer or external storage device via a network (for example, the Internet, a local area network or other wide area networks or wireless networks) and network adapter or interface  416 . From the network adapter or interface  416 , the programs may be loaded into the computer readable storage media  408 . The network may comprise copper wires, optical fibers, wireless transmission, routers, firewalls, switches, gateway computers and edge servers. 
     The computing system can also include a display screen  420 , a keyboard or keypad  422 , and a computer mouse or touchpad  424 . Device drivers  412  interface to display screen  420  for imaging, to keyboard or keypad  422 , to computer mouse or touchpad  424 , and/or to display screen  420  for pressure sensing of alphanumeric character entry and user selections. The device drivers  412 , RAY drive or interface  414 , and network adapter or interface  416  can comprise hardware and software stored in computer readable storage media  408  and/or ROM  406 . 
     The present invention may be a system, a method, and/or a computer program product at any possible technical detail level of integration. The computer program product may include a computer readable storage medium (or media) having computer readable program instructions thereon for causing a processor to carry out aspects of the present invention. 
     The computer readable storage medium can be a tangible device that can retain and store instructions for use by an instruction execution device. The computer readable storage medium may be, for example, but is not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of the computer readable storage medium includes the following: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanically encoded device such as punch-cards or raised structures in a groove having instructions recorded thereon, and any suitable combination of the foregoing. A computer readable storage medium, as used herein, is not to be construed as being transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission media (e.g., light pulses passing through a fiber-optic cable), or electrical signals transmitted through a wire. 
     Computer readable program instructions described herein can be downloaded to respective computing/processing devices from a computer readable storage medium or to an external computer or external storage device via a network, for example, the Internet, a local area network, a wide area network and/or a wireless network. The network may comprise copper transmission cables, optical transmission fibers, wireless transmission, routers, firewalls, switches, gateway computers and/or edge servers. A network adapter card or network interface in each computing/processing device receives computer readable program instructions from the network and forwards the computer readable program instructions for storage in a computer readable storage medium within the respective computing/processing device. 
     Computer readable program instructions for carrying out operations of the present invention may be assembler instructions, instruction-set-architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state-setting data, configuration data for integrated circuitry, or either source code or object code written in any combination of one or more programming languages, including an object oriented programming language such as Smalltalk, C++, or the like, and procedural programming languages, such as the “C” programming language or similar programming languages. The computer readable program instructions may execute entirely on the user&#39;s computer, partly on the user&#39;s computer, as a stand-alone software package, partly on the user&#39;s computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user&#39;s computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider). In some embodiments, electronic circuitry including, for example, programmable logic circuitry, field-programmable gate arrays (FPGA), or programmable logic arrays (PLA) may execute the computer readable program instructions by utilizing state information of the computer readable program instructions to personalize the electronic circuitry, in order to perform aspects of the present invention. 
     Aspects of the present invention are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer readable program instructions. 
     These computer readable program instructions may be provided to a processor of a computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. These computer readable program instructions may also be stored in a computer readable storage medium that can direct a computer, a programmable data processing apparatus, and/or other devices to function in a particular manner, such that the computer readable storage medium having instructions stored therein comprises an article of manufacture including instructions which implement aspects of the function/act specified in the flowchart and/or block diagram block or blocks. 
     The computer readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus or other device to produce a computer implemented process, such that the instructions which execute on the computer, other programmable apparatus, or other device implement the functions/acts specified in the flowchart and/or block diagram block or blocks. 
     The flowchart and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the blocks may occur out of the order noted in the Figures. For example, two blocks shown in succession may, in fact, be accomplished as one step, executed concurrently, substantially concurrently, in a partially or wholly temporally overlapping manner, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts or carry out combinations of special purpose hardware and computer instructions. 
     Cloud Computing 
     It is to be understood that although this disclosure includes a detailed description on cloud computing, implementation of the teachings recited herein are not limited to a cloud computing environment. Rather, embodiments of the present invention are capable of being implemented in conjunction with any other type of computing environment now known or later developed. 
     Cloud computing is a model of service delivery for enabling convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, network bandwidth, servers, processing, memory, storage, applications, virtual machines, and services) that can be rapidly provisioned and released with minimal management effort or interaction with a provider of the service. This cloud model may include at least five characteristics, at least three service models, and at least four deployment models. 
     Characteristics are as follows: 
     On-demand self-service: a cloud consumer can unilaterally provision computing capabilities, such as server time and network storage, as needed automatically without requiring human interaction with the service&#39;s provider. 
     Broad network access: capabilities are available over a network and accessed through standard mechanisms that promote use by heterogeneous thin or thick client platforms (e.g., mobile phones, laptops, and PDAs). 
     Resource pooling: the provider&#39;s computing resources are pooled to serve multiple consumers using a multi-tenant model, with different physical and virtual resources dynamically assigned and reassigned according to demand. There is a sense of location independence in that the consumer generally has no control or knowledge over the exact location of the provided resources but may be able to specify location at a higher level of abstraction (e.g., country, state, or datacenter). 
     Rapid elasticity: capabilities can be rapidly and elastically provisioned, in some cases automatically, to quickly scale out and rapidly released to quickly scale in. To the consumer, the capabilities available for provisioning often appear to be unlimited and can be purchased in any quantity at any time. 
     Measured service: cloud systems automatically control and optimize resource use by leveraging a metering capability at some level of abstraction appropriate to the type of service (e.g., storage, processing, bandwidth, and active user accounts). Resource usage can be monitored, controlled, and reported, providing transparency for both the provider and consumer of the utilized service. 
     Service Models are as follows: 
     Software as a Service (SaaS): the capability provided to the consumer is to use the provider&#39;s applications running on a cloud infrastructure. The applications are accessible from various client devices through a thin client interface such as a web browser (e.g., web-based e-mail). The consumer does not manage or control the underlying cloud infrastructure including network, servers, operating systems, storage, or even individual application capabilities, with the possible exception of limited user-specific application configuration settings. 
     Platform as a Service (PaaS): the capability provided to the consumer is to deploy onto the cloud infrastructure consumer-created or acquired applications created using programming languages and tools supported by the provider. The consumer does not manage or control the underlying cloud infrastructure including networks, servers, operating systems, or storage, but has control over the deployed applications and possibly application hosting environment configurations. 
     Infrastructure as a Service (IaaS): the capability provided to the consumer is to provision processing, storage, networks, and other fundamental computing resources where the consumer is able to deploy and run arbitrary software, which can include operating systems and applications. The consumer does not manage or control the underlying cloud infrastructure but has control over operating systems, storage, deployed applications, and possibly limited control of select networking components (e.g., host firewalls). 
     Deployment Models are as follows: 
     Private cloud: the cloud infrastructure is operated solely for an organization. It may be managed by the organization or a third party and may exist on-premises or off-premises. 
     Community cloud: the cloud infrastructure is shared by several organizations and supports a specific community that has shared concerns (e.g., mission, security requirements, policy, and compliance considerations). It may be managed by the organizations or a third party and may exist on-premises or off-premises. 
     Public cloud: the cloud infrastructure is made available to the general public or a large industry group and is owned by an organization selling cloud services. 
     Hybrid cloud: the cloud infrastructure is a composition of two or more clouds (private, community, or public) that remain unique entities but are bound together by standardized or proprietary technology that enables data and application portability (e.g., cloud bursting for load-balancing between clouds). 
     A cloud computing environment is service oriented with a focus on statelessness, low coupling, modularity, and semantic interoperability. At the heart of cloud computing is an infrastructure that includes a network of interconnected nodes. 
     Referring now to  FIG.  5   , illustrative cloud computing environment  50  is depicted. As shown, cloud computing environment  50  includes one or more cloud computing nodes  10  with which local computing devices used by cloud consumers, such as, for example, personal digital assistant (PDA) or cellular telephone  54 A, desktop computer  54 B, laptop computer  54 C, and/or automobile computer system  54 N may communicate. Nodes  10  may communicate with one another. They may be grouped (not shown) physically or virtually, in one or more networks, such as Private, Community, Public, or Hybrid clouds as described hereinabove, or a combination thereof. This allows cloud computing environment  50  to offer infrastructure, platforms and/or software as services for which a cloud consumer does not need to maintain resources on a local computing device. It is understood that the types of computing devices  54 A-N shown in  FIG.  5    are intended to be illustrative only and that computing nodes  10  and cloud computing environment  50  can communicate with any type of computerized device over any type of network and/or network addressable connection (e.g., using a web browser). 
     Referring now to  FIG.  6   , a set of functional abstraction layers provided by cloud computing environment  50  ( FIG.  5   ) is shown. It should be understood in advance that the components, layers, and functions shown in  FIG.  6    are intended to be illustrative only and embodiments of the invention are not limited thereto. As depicted, the following layers and corresponding functions are provided: 
     Hardware and software layer  60  includes hardware and software components. Examples of hardware components include: mainframes  61 ; RISC (Reduced Instruction Set Computer) architecture based servers  62 ; servers  63 ; blade servers  64 ; storage devices  65 ; and networks and networking components  66 . In some embodiments, software components include network application server software  67  and database software  68 . 
     Virtualization layer  70  provides an abstraction layer from which the following examples of virtual entities may be provided: virtual servers  71 ; virtual storage  72 ; virtual networks  73 , including virtual private networks; virtual applications and operating systems  74 ; and virtual clients  75 . 
     In one example, management layer  80  may provide the functions described below. Resource provisioning  81  provides dynamic procurement of computing resources and other resources that are utilized to perform tasks within the cloud computing environment. Metering and Pricing  82  provide cost tracking as resources are utilized within the cloud computing environment, and billing or invoicing for consumption of these resources. In one example, these resources may include application software licenses. Security provides identity verification for cloud consumers and tasks, as well as protection for data and other resources. User portal  83  provides access to the cloud computing environment for consumers and system administrators. Service level management  84  provides cloud computing resource allocation and management such that required service levels are met. Service Level Agreement (SLA) planning and fulfillment  85  provide pre-arrangement for, and procurement of, cloud computing resources for which a future requirement is anticipated in accordance with an SLA. 
     Workloads layer  90  provides examples of functionality for which the cloud computing environment may be utilized. Examples of workloads and functions which may be provided from this layer include: mapping and navigation  91 ; software development and lifecycle management  92 ; virtual classroom education delivery  93 ; data analytics processing  94 ; transaction processing  95 ; and code coverage processing  96 . 
     A computer program product of the present invention comprises one or more computer readable hardware storage devices having computer readable program code stored therein, said program code executable by one or more processors to implement the methods of the present invention. 
     A computer system of the present invention comprises one or more processors, one or more memories, and one or more computer readable hardware storage devices, said one or more hardware storage device containing program code executable by the one or more processors via the one or more memories to implement the methods of the present invention. 
     The descriptions of the various embodiments of the present invention have been presented for purposes of illustration, but are not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein was chosen to best explain the principles of the embodiments, the practical application or technical improvement over technologies found in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein. 
     Improvements and modifications can be made to the foregoing without departing from the scope of the present invention.