Activity: Input Space Grammar

(no submission)
Purpose: Applying syntax-based testing to input space to create test cases; get ready to work on homework assignment, and prepare for quiz 5 and the final exam

You may make a copy of a worksheet and complete this activity or type your answers in any text editor.

You may work alone or with at most two other students in this course.

Consider a simple stack class that has five operations: 
Init:     Create a new stack
Push:     Add an item to the stack; the item is placed at the top of the stack
Pop:      Pop an element from the top of the stack, remove that item from the stack
Peek:     Obtain the item present at the top of the stack, does not remove it from the stack
Dispose:  Destroy an existing stack

The following BNF grammar constrains how the stack is used.

A legal use is a sequence of stack operations that is in the language defined by the grammar.
For example, the sequence "Init Push Pop Dispose" is legal.

An illegal use is a sequence of stack operations that is not in the language defined by the grammar.
For example, the sequence "Init Peek" is illegal. 

DoIt ::=  X | X DoIt
X    ::=  "Init" "Dispose" | "Init" Y "Dispose"
Y    ::=  "Push" | "Push" Y | "Push" Z | "Push" Y Z
Z    ::=  "Peek" | "Pop" | "Peek" "Pop"
  1. Is it legal to Peek a non-empty stack? Justify your answer by showing a derivation in the grammar.
  2. Give a valid input (strings) that satisfy Terminal Symbol Coverage (TSC)
  3. Give a minimal set of test requirements that satisfy Production Coverage (PDC)
Consider the following regular expression for bank example and answer the questions 
  ("deposit" account amount | "debit" account amount)*
  1. Draw a Finite State Machine (FSM) to represent the grammar
  2. Create 3 possible input strings from the grammar
Consider the following Backus-Naur Form (BNF) grammar for bank example and answer the questions 
  bank     ::=  action*
  action   ::=  dep  |  deb
  dep      ::=  "deposit" account amount
  deb      ::=  "debit" account amount
  account  ::=  digit4
  amount   ::=  "$" digit+ "." digit2
  digit    ::=  "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9"
  1. Draw a Finite State Machine (FSM) to represent the grammar
  2. Create 3 possible ground (input) strings from the grammar
  3. Apply input grammar mutation operators to create mutants
    • Nonterminal replacement operator replaces every nonterminal symbol in a production
        dep ::= "deposit" account amount   by other nonterminal symbols
    • Terminal replacement operator replaces every terminal symbol in a production
        amount ::= "$" digit+ "." digit2   by other terminal symbols
    • Terminal and nonterminal deletion operator deletes every terminal and nonterminal symbol in a production
        dep ::= "deposit" account amount  
    • Terminal and nonterminal duplication operator duplicates every terminal and nonterminal symbol in a production
        dep ::= "deposit" account amount  
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Last updated 2025-11-01 22:08