Common Software Errors

Common Software Errors
Introduction
This document takes you through whirl-wind tour of common software errors. This is an excellent aid for software testing. It helps you to identify errors systematically and increases the efficiency of software testing and improves testing productivity. For more information, please refer Testing Computer Software, Wiley Edition.

Type of Errors
• User Interface Errors
• Error Handling
• Boundary related errors
• Calculation errors
• Initial and Later states
• Control flow errors
• Errors in Handling or Interpreting Data
• Race Conditions
• Load Conditions
• Hardware
• Source, Version and ID Control
• Testing Errors

Let us go through details of each kind of error.

User Interface Errors
Functionality
Sl No Possible Error Conditions
1 Excessive Functionality
2 Inflated impression of functionality
3 Inadequacy for the task at hand
4 Missing function
5 Wrong function
6 Functionality must be created by user
7 Doesn't do what the user expects


Communication
Missing Information
Sl No Possible Error Conditions
1 No on Screen instructions
2 Assuming printed documentation is already available.
3 Undocumented features
4 States that appear impossible to exit
5 No cursor
6 Failure to acknowledge input
7 Failure to show activity during long delays
8 Failure to advise when a change will take effect
9 Failure to check for the same document being opened twice
Wrong, misleading, confusing information
10 Simple factual errors
11 Spelling errors
12 Inaccurate simplifications
13 Invalid metaphors
14 Confusing feature names
15 More than one name for the same feature
16 Information overland
17 When are data saved
18 Wrong function
19 Functionality must be created by user
20 Poor external modularity
Help text and error messages
21 Inappropriate reading levels
22 Verbosity
23 Inappropriate emotional tone
24 Factual errors
25 Context errors
26 Failure to identify the source of error
27 Forbidding a resource without saying why
28 Reporting non-errors
29 Failure to highlight the part of the screen
30 Failure to clear highlighting
31 Wrong/partial string displayed
32 Message displayed for too long or not long enough
Display Layout
33 Poor aesthetics in screen layout
34 Menu Layout errors
35 Dialog box layout errors
36 Obscured Instructions
37 Misuse of flash
38 Misuse of color
39 Heavy reliance on color
40 Inconsistent with the style of the environment
41 Cannot get rid of on screen information
Output
42 Can't output certain data
43 Can't redirect output
44 Format incompatible with a follow-up process
45 Must output too little or too much
46 Can't control output layout
47 Absurd printout level of precision
48 Can't control labeling of tables or figures
49 Can't control scaling of graphs
Performance
50 Program Speed
51 User Throughput
52 Can't redirect output
53 Perceived performance
54 Slow program
55 slow echoing
56 how to reduce user throughput
57 Poor responsiveness
58 No type ahead
59 No warning that the operation takes long time
60 No progress reports
61 Problems with time-outs
62 Program pesters you


Program Rigidity
User tailorability
Sl No Possible Error Conditions
1 Can't turn off case sensitivity
2 Can't tailor to hardware at hand
3 Can't change device initialization
4 Can't turn off automatic changes
5 Can't slow down/speed up scrolling
6 Can't do what you did last time
7 Failure to execute a customization commands
8 Failure to save customization commands
9 Side effects of feature changes
10 Can't turn off the noise
11 Infinite tailorability
Who is in control?
12 Unnecessary imposition of a conceptual style
13 Novice friendly, experienced hostile
14 Surplus or redundant information required
15 Unnecessary repetition of steps
16 Unnecessary limits


Command Structure and Rigidity
Inconsistencies
Sl No Possible Error Conditions
1 Optimizations
2 Inconsistent syntax
3 Inconsistent command entry style
4 Inconsistent abbreviations
5 Inconsistent termination rule
6 Inconsistent command options
7 Similarly named commands
8 Inconsistent Capitalization
9 Inconsistent menu position
10 Inconsistent function key usage
11 Inconsistent error handling rules
12 Inconsistent editing rules
13 Inconsistent data saving rules
Time Wasters
14 Garden paths
15 choice can't be taken
16 Are you really, really sure
17 Obscurely or idiosyncratically named commands
Menus
18 Excessively complex menu hierarchy
19 Inadequate menu navigation options
20 Too many paths to the same place
21 You can't get there from here
22 Related commands relegated to unrelated menus
23 Unrelated commands tossed under the same menu
Command Lines
24 Forced distinction between uppercase and lowercase
25 Reversed parameters
26 Full command names are not allowed
27 Abbreviations are not allowed
28 Demands complex input on one line
29 no batch input
30 can't edit commands
Inappropriate use of key board
31 Failure to use cursor, edit, or function keys
32 Non std use of cursor and edit keys
33 non-standard use of function keys
34 Failure to filter invalid keys
35 Failure to indicate key board state changes


Missing Commands
State transitions
Sl No Possible Error Conditions
1 Can't do nothing and leave
2 Can't quit mid-program
3 Can't stop mid-command
4 Can't pause
Disaster prevention
5 No backup facility
6 No undo
7 No are you sure
8 No incremental saves
Disaster prevention
9 Inconsistent menu position
10 Inconsistent function key usage
11 Inconsistent error handling rules
12 Inconsistent editing rules
13 Inconsistent data saving rules
Error handling by the user
14 No user specifiable filters
15 Awkward error correction
16 Can't include comments
17 Can't display relationships between variables
Miscellaneous
18 Inadequate privacy or security
19 Obsession with security
20 Can't hide menus
21 Doesn't support standard OS features
22 Doesn't allow long names

Error Handling

Error prevention
Sl No Possible Error Conditions
1 Inadequate initial state validation
2 Inadequate tests of user input
3 Inadequate protection against corrupted data
4 Inadequate tests of passed parameters
5 Inadequate protection against operating system bugs
6 Inadequate protection against malicious use
7 Inadequate version control


Error Detection
Sl No Possible Error Conditions
1 ignores overflow
2 ignores impossible values
3 ignores implausible values
4 ignores error flag
5 ignores hardware fault or error conditions
6 data comparison

Error Recovery
Sl No Possible Error Conditions
1 automatic error detection
2 failure to report error
3 failure to set an error flag
4 where does the program go back to
5 aborting errors
6 recovery from hardware problems
7 no escape from missing disks


Boundary related errors

Sl No Possible Error Conditions
1 Numeric boundaries
2 Equality as boundary
3 Boundaries on numerosity
4 Boundaries in space
5 Boundaries in time
6 Boundaries in loop
7 Boundaries in memory
8 Boundaries with data structure
9 Hardware related boundaries
10 Invisible boundaries
11 Mishandling of boundary case
12 Wrong boundary
13 Mishandling of cases outside boundary

Calculation Errors

Sl No Possible Error Conditions
1 Bad Logic
2 Bad Arithmetic
3 Imprecise Calculations
4 Outdated constants
5 Calculation errors
6 Impossible parenthesis
7 Wrong order of calculations
8 Bad underlying functions
9 Overflow and Underflow
10 Truncation and Round-off error
11 Confusion about the representation of data
12 Incorrect conversion from one data representation to another
13 Wrong Formula
14 Incorrect Approximation


Race Conditions

Sl No Possible Error Conditions
1 Races in updating data
2 Assumption that one event or task finished before another begins
3 Assumptions that one event or task has finished before another begins
4 Assumptions that input won't occur during a brief processing interval
5 Assumptions that interrupts won't occur during brief interval
6 Resource races
7 Assumptions that a person, device or process will respond quickly
8 Options out of sync during display changes
9 Tasks starts before its prerequisites are met
10 Messages cross or don't arrive in the order sent

Initial and Later States

Sl No Possible Error Conditions
1 Failure to set data item to zero
2 Failure to initialize a loop-control variable
3 Failure to initialize a or re-initialize a pointer
4 Failure to clear a string
5 Failure to initialize a register
6 Failure to clear a flag
7 Data were supposed to be initialized elsewhere
8 Failure to re-initialize
9 Assumption that data were not re-initialized
10 Confusion between static and dynamic storage
11 Data modifications by side effect
12 Incorrect initialization
Control Flow Errors

Program runs amok
Sl No Possible Error Conditions
1 Jumping to a routine that isn't resident
2 Re-entrance
3 Variables contains embedded command names
4 Wrong returning state assumed
5 Exception handling based exits

Return to wrong place
Sl No Possible Error Conditions
1 Corrupted Stack
2 Stack underflow/overflow
3 GOTO rather than RETURN from sub-routine

Interrupts
Sl No Possible Error Conditions
1 Wrong interrupt vector
2 Failure to restore or update interrupt vector
3 Invalid restart after an interrupt
4 Failure to block or un-block interrupts


Program Stops
Sl No Possible Error Conditions
1 Dead crash
2 Syntax error reported at run time
3 Waiting for impossible condition or combinations of conditions
4 Wrong user or process priority

Error Detection
Sl No Possible Error Conditions
1 infinite loop
2 Wrong starting value for the loop control variables
3 Accidental change of loop control variables
4 Command that do or don't belong inside the loop
5 Command that do or don't belong inside the loop
6 Improper loop nesting

If Then Else , Or may not
Sl No Possible Error Conditions
1 Wrong inequalities
2 Comparison sometimes yields wrong result
3 Not equal verses equal when there are three cases
4 Testing floating point values for equality
5 confusion between inclusive and exclusive OR
6 Incorrectly negating a logical expression
7 Assignment equal instead of test equal
8 Commands being inside the THEN or ELSE clause
9 Commands that don't belong either case
10 Failure to test a flag
11 Failure to clear a flag


Multiple Cases
Sl No Possible Error Conditions
1 Missing default
2 Wrong default
3 Missing cases
4 Overlapping cases
5 Invalid or impossible cases
6 Commands being inside the THEN or ELSE clause
7 Case should be sub-divided

Errors Handling or Interpreting Data

Problems in passing data between routines
Sl No Possible Error Conditions
1 Parameter list variables out of order or missing
2 Data Type errors
3 Aliases and shifting interpretations of the same area of memory
4 Misunderstood data values
5 inadequate error information
6 Failure to clean up data on exception handling
7 Outdated copies of data
8 Related variable get out of synch
9 Local setting of global data
10 Global use of local variables
11 Wrong mask in bit fields
12 Wrong value from table

Data boundaries
Sl No Possible Error Conditions
1 Un-terminated null strings
2 Early end of string
3 Read/Write past end of data structure or an element in it

Read outside the limits of message buffer
Sl No Possible Error Conditions
1 Complier padding to word boundaries
2 value stack underflow/overflow
3 Trampling another process's code or data

Messaging Problems
Sl No Possible Error Conditions
1 Messages sent to wrong process or port
2 Failure to validate an incoming message
3 Lost or out of synch messages
4 Message sent to only N of N+1 processes

Data Storage corruption
Sl No Possible Error Conditions
1 Overwritten changes
2 Data entry not saved
3 Too much data for receiving process to handle
4 Overwriting a file after an error exit or user abort

Load Conditions

Sl No Possible Error Conditions
1 Required resources are not available
2 No available large memory area
3 Input buffer or queue not deep enough
4 Doesn't clear item from queue, buffer or stock
5 Lost Messages
6 Performance costs
7 Race condition windows expand
8 Doesn't abbreviate under load
9 Doesn't recognize that another process abbreviates output under load
10 Low priority tasks not put off
11 Low priority tasks never done


Doesn't return a resource
Sl No Possible Error Conditions
1 Doesn't indicate that it's done with a device
2 Doesn't erase old files from mass storage
3 Doesn't return unused memory
4 Wastes computer time

Hardware

Sl No Possible Error Conditions
1 Wrong Device
2 Wrong Device Address
3 Device unavailable
4 Device returned to wrong type of pool
5 Device use forbidden to caller
6 Specifies wrong privilege level for the device
7 Noisy Channel
8 Channel goes down
9 Time-out problems
10 Wrong storage device
11 Doesn't check the directory of current disk
12 Doesn't close the file
13 Unexpected end of file
14 Disk sector bug and other length dependent errors
15 Wrong operation or instruction codes
16 Misunderstood status or return code
17 Underutilizing device intelligence
18 Paging mechanism ignored or misunderstood
19 Ignores channel throughput limits
20 Assuming device is or isn't or should be or shouldn't be initialized
21 Assumes programmable function keys are programmed correctly

Source, Version, ID Control

Sl No Possible Error Conditions
1 Old bugs mysteriously re appear
2 Failure to update multiple copies of data or program files
3 No title
4 No version ID
5 Wrong version number of title screen
6 No copy right message or bad one
7 Archived source doesn't compile into a match for shipping code
8 Manufactured disks don't work or contain wrong code or data

Testing Errors

Missing bugs in the program
Sl No Possible Error Conditions
1 Failure to notice a problem
2 You don't know what the correct test results are
3 You are bored or inattentive
4 Misreading the Screen
5 Failure to report problem
6 Failure to execute a planned test
7 Failure to use the most promising test case
8 Ignoring programmer's suggestions


Finding bugs that aren't in the program
Sl No Possible Error Conditions
1 Errors in testing programs
2 Corrupted data files
3 Misinterpreted specifications or documentation


Poor reporting
Sl No Possible Error Conditions
1 Illegible reports
2 Failure to make it clear how to reproduce the problem
3 Failure to say you can't reproduce the problem
4 Failure to check your report
5 Failure to report timing dependencies
6 Failure to simplify conditions
7 Concentration on trivia
8 Abusive language


Poor Tracking and follow-up
Sl No Possible Error Conditions
1 Failure to provide summary report
2 Failure to re-report serious bug
3 Failure to check for unresolved problems just before release
4 Failure to verify fixes