Conditions.md

Conditions

Testo language supports condition management with an if clause. If-statements can be placed at the same level as actions - e.g. in commands body. If-statements have the next syntax:

if (expression) {
	action1
	action2
	action3
	...
} [else {
	action1
	action2
	...
}]

The syntax is pretty much straightforward: an if clause consists of an expression which may be evaluated into either true or false. If the expression value is true, the main action block is run. If the exression is equal to false, then the else action block is reached (if there is any else clause).

Inside both action blocks ("main" and "else") all the actions, nested conditions and loops are allowed.

Conditions may be stacked as follows:

if (expression) {

} else if {

} else if {

}
...

Expressions

Expressions are entities which could be evaluated into a true or a false. At the moment expressions are used only inside the if clause.

Possible expressions in Testo-lang are listed below:

• A string. An empty (zero-length) string is treated as a false, othwerwise as a true.
• A negation (NOT <expr>). Logical complement to the expr.
• DEFINED var. Returns true if the var param is defined. Which means its value could be obtained, either from the static declaration, or from the command line argument --param (even if the value is an empty string). False otherwise.
• Comparisons. Described below.
• Logical conjunction (<expr1> AND <expr2>). Returns true if both expr1 AND expr2 are true. False otherwise.
• Logical disjunction (<exrp1> OR <expr2>). Returns true if one or both of expr1 and expr2 are true. False otherwise.
• Only for if statements placed in virtual machines commands. Checking the contents of screen with select expressions (check <select_expr> [timeout timeout_spec] [interval interval_spec]). For select_expr specifications see here. The checks go on until the select_expr is found (check result is true) or the timeout is triggered (check result is false). Default timeout is 1ms which means just one instant check will be performed. You can adjust the checks frequency with the interval argument (default value is 1s).

You can use parentheses to group up the expressions.

Comparisons

Testo lang allows you to compare strings. The comparison result is a boolean (true or false).

Possible comparison types in Testo lang:

• <string1> STREQUAL <string2> - returns true if both strings are the same. False otherwise.
• <string1> STRLESS <string2> - returns true if string1 lexicographically less than string2. False otherwise.
• <string1> STRGREATER <string2> - returns true if string1 lexicographically greater than string2. False otherwise.
• <string1> EQUAL <string2> - applicable if both string1 and string2 are convertible to integers. Returns true if after conversion to integers both operands will be equal. False otherwise. If string1 or string2 are not convertible to integers, an error will be generated.
• <string1> LESS <string2> - applicable if both string1 and string2 are convertible to integers. Returns true if after conversion to integers left operand is less than the right. False otherwise. If string1 or string2 are not convertible to integers, an error will be generated.
• <string1> GREATER <string2> - applicable if both string1 and string2 are convertible to integers. Returns true if after conversion to integers left operand is greater than the right one. False otherwise. If string1 or string2 are not convertible to integers, an error will be generated.

Examples

"SOME STRING" # true
"" # false
"${some_var}" # The value depends on the some_var param. An error will be generated if the some_var param is not defined
DEFINED some_var # true if some_var is defined (even if the value is a zero-length string)
check "Hello world" # true, if there is a text "Hello world" on the screen
"5" EQUAL "${some_var}" # true, if "${some_var}" has the value "5"
"ABC" STRLESS "BCD" # true
NOT ("ABC" STRLESS "BCD") # false
NOT ("ABC" STRLESS "BCD") OR "5" EQUAL "5" # true
NOT ("ABC" STRLESS "BCD" AND "5" EQUAL "5") # false