Parameterizing Objects in spock - groovy

I have a problem with parameterizations of list of object by using spock where block. It seems the ListInput value is not taking from the where clause and always coming null value. I have verified the same feature for string and other primitive types and it is working fine.
Does Spock support parameterizations objects ? If yes what is the issue here .
def "check Param Of List of Objects"()
{
expect:
def a= hasflag(ListInput);
a== flag
where:
ListInput | flag
BOList1 | true
BOList2 | false
}
Here the type of BOList1 is an java ArrayList contains the object

You haven't really provided enough information for a definitive answer but I'll try to help.
The where block isn't exactly just a block of code, it's more like a number of parameters passed to a method. It can do a lot, but sometimes you need to pass your code a little differently.
Of note:
- Void methods aren't allowed (but you can get around this using .with{} )
- An iterative parameter cannot also be a derived parameter (constructed from other parameters)
- If you're referencing class level variables (defined within the class but outside this test) they need to be given the #Shared annotation for your tests to have access.
Given more information about where your lists are coming from will help me give better advice.
Final tip; explicitly typecast your parameters to see if that gives you anymore information
def "check Param Of List of Objects"(ArrayList listInput, boolean flag) {
expect:
flag == hasflag(ListInput);
where:
listInput | flag
BOList1 | true
BOList2 | false
}

Related

Is it possible to get the name of variable in Groovy?

I would like to know if it is possible to retrieve the name of a variable.
For example if I have a method:
def printSomething(def something){
//instead of having the literal String something, I want to be able to use the name of the variable that was passed
println('something is: ' + something)
}
If I call this method as follows:
def ordinary = 58
printSomething(ordinary)
I want to get:
ordinary is 58
On the other hand if I call this method like this:
def extraOrdinary = 67
printSomething(extraOrdinary)
I want to get:
extraOrdinary is 67
Edit
I need the variable name because I have this snippet of code which runs before each TestSuite in Katalon Studio, basically it gives you the flexibility of passing GlobalVariables using a katalon.features file. The idea is from: kazurayam/KatalonPropertiesDemo
#BeforeTestSuite
def sampleBeforeTestSuite(TestSuiteContext testSuiteContext) {
KatalonProperties props = new KatalonProperties()
// get appropriate value for GlobalVariable.hostname loaded from katalon.properties files
WebUI.comment(">>> GlobalVariable.G_Url default value: \'${GlobalVariable.G_Url}\'");
//gets the internal value of GlobalVariable.G_Url, if it's empty then use the one from katalon.features file
String preferedHostname = props.getProperty('GlobalVariable.G_Url')
if (preferedHostname != null) {
GlobalVariable.G_Url = preferedHostname;
WebUI.comment(">>> GlobalVariable.G_Url new value: \'${preferedHostname}\'");
} else {
WebUI.comment(">>> GlobalVariable.G_Url stays unchanged");
}
//doing the same for other variables is a lot of duplicate code
}
Now this only handles 1 variable value, if I do this for say 20 variables, that is a lot of duplicate code, so I wanted to create a helper function:
def setProperty(KatalonProperties props, GlobalVariable var){
WebUI.comment(">>> " + var.getName()" + default value: \'${var}\'");
//gets the internal value of var, if it's null then use the one from katalon.features file
GlobalVariable preferedVar = props.getProperty(var.getName())
if (preferedVar != null) {
var = preferedVar;
WebUI.comment(">>> " + var.getName() + " new value: \'${preferedVar}\'");
} else {
WebUI.comment(">>> " + var.getName() + " stays unchanged");
}
}
Here I just put var.getName() to explain what I am looking for, that is just a method I assume.
Yes, this is possible with ASTTransformations or with Macros (Groovy 2.5+).
I currently don't have a proper dev environment, but here are some pointers:
Not that both options are not trivial, are not what I would recommend a Groovy novice and you'll have to do some research. If I remember correctly either option requires a separate build/project from your calling code to work reliable. Also either of them might give you obscure and hard to debug compile time errors, for example when your code expects a variable as parameter but a literal or a method call is passed. So: there be dragons. That being said: I have worked a lot with these things and they can be really fun ;)
Groovy Documentation for Macros
If you are on Groovy 2.5+ you can use Macros. For your use-case take a look at the #Macro methods section. Your Method will have two parameters: MacroContext macroContext, MethodCallExpression callExpression the latter being the interesting one. The MethodCallExpression has the getArguments()-Methods, which allows you to access the Abstract Syntax Tree Nodes that where passed to the method as parameter. In your case that should be a VariableExpression which has the getName() method to give you the name that you're looking for.
Developing AST transformations
This is the more complicated version. You'll still get to the same VariableExpression as with the Macro-Method, but it'll be tedious to get there as you'll have to identify the correct MethodCallExpression yourself. You start from a ClassNode and work your way to the VariableExpression yourself. I would recommend to use a local transformation and create an Annotation. But identifying the correct MethodCallExpression is not trivial.
no. it's not possible.
however think about using map as a parameter and passing name and value of the property:
def printSomething(Map m){
println m
}
printSomething(ordinary:58)
printSomething(extraOrdinary:67)
printSomething(ordinary:11,extraOrdinary:22)
this will output
[ordinary:58]
[extraOrdinary:67]
[ordinary:11, extraOrdinary:22]

Accessing a variable defined in another function in Groovy

I am new to Groovy.
I have a function in which I am writing a value to map.
def addTraceEntry(key, value) {
def traceability = [:]
traceability[key] = value.trim()
println "This print happens in function addTraceEntry " + traceability
}
I have another function that needs to verify whether the above function works properly.
def testAddTraceEntry() {
def key = 'test_key'
def value = 'test_value'
addTraceEntry(key, value)
println "This print happens in function testAddTraceEntry " + traceability
assert value == traceability[key]
}
I am invoking the testAddTraceEntry() function using the function name:
testAddTraceEntry()
When I run this, I get the ERROR:
This print happens in function addTraceEntry [test_key:test_value]
Caught: groovy.lang.MissingPropertyException: No such property: traceability for class: HelloWorld
groovy.lang.MissingPropertyException: No such property: traceability for class: HelloWorld
at HelloWorld.testAddTraceEntry(HelloWorld.groovy:53)
at HelloWorld.run(HelloWorld.groovy:57)
In the function testAddTraceEntry it clearly does not know the value of traceability so seems like its giving an ERROR for that.
I tried to return the value of traceability.
def addTraceEntry(key, value) {
def traceability = [:]
traceability[key] = value.trim()
println "This print happens in function addTraceEntry " + traceability
return traceability
}
But this yields the same ERROR.
There are a bunch of things worth mentioning after seeing the code you have wrote.
First thing - the scope of variables and encapsulation. Let's throw away technicalities for a moment and focus on something even more important. In method addTraceEntry you persist some state, which is fine. However, the implementation of the method testAddTraceEntry reveals that this method tries to know way to much about the implementation details of addTraceEntry. It encapsulates (hides in other words) persistence logic (from the API point of view you, as a caller, don't know that it persists key and a value inside the map) and that is why testAddTraceEntry should never ever make assumptions that calling this method mutated some structure. If you do so, then:
your test method contracts side effects and not the expected business logic (storing data in some kind of global map - don't do it. Ever)
your test blocks any evolution of tested method implementation - imagine, that you decided to store key and value in a different structure. You may do it without breaking any API contract (your function produces the same results), but the test method will fail and you will have to modify it.
Second thing - your addTraceEntry method always produces a map with a single entry. It doesn't make much sense and if you call your function let's say 4 times you will end up with 4 maps where each one of them contain a single key mapped to a single value.
There are at least various ways to improve implementation of your methods. The simplest thing you can do is to implement a class that encapsulates logic for storing keys and values. Consider following example:
import java.util.concurrent.ConcurrentHashMap
import java.util.concurrent.ConcurrentMap
class TraceEntriesStorage {
private final ConcurrentMap<String, Object> entries = [:] as ConcurrentHashMap
def addTraceEntry(String key, Object value) {
entries.put(key, value)
}
def containsTraceEntry(String key) {
return entries.containsKey(key)
}
def retrieveTraceEntryForKey(String key) {
return entries.get(key)
}
}
This is a simple class with 3 short methods. It stores trace entries inside the internal concurrent map (to solve problems with concurrent access). Now, your test method could look like this:
def storage = new TraceEntriesStorage()
storage.addTraceEntry("test_key", "test_value")
assert storage.containsTraceEntry("test_key")
assert storage.retrieveTraceEntryForKey("test_key") == "test_value"
You create an instance of this class, you add an entry and you check if methods containsTraceEntry and retrieveTraceEntryForKey return expected values. As you can see it doesn't matter where we stored this trace entry - it matters that the class we have implemented behaves as expected. To make this test method even better you could add an assertion that checks if there is no trace entry for test_key before we actually insert it - this way we know that adding trace entry change internal state of the class. But what is nice in this approach is that as long as we don't break the contract, we can experiment and modify implementation of TraceEntriesStorage. Because what is most important - adding trace entries have to allow to retrieve them back from the object. How it gets stored, where it gets stored - it doesn't matter.
I hope you find this answer useful and it will help you in learning Groovy and designing a better programs. Happy hacking!
You need to combine adding the return statement to addTraceEntry() with assigning the returned value to a variable in testAddTraceEntry():
def traceability = addTraceEntry(key, value)

Perl 6 - Is it possible to create an attribute trait that set a meta-attribute?

I try to create an attribute trait. The use case is to mark some attributes of a class as "crudable" in the context of an objects-to-documents-mapping while other are not.
role crud {
has Bool $.crud is default(True);
}
multi trait_mod:<is>(Attribute $a, crud, $arg) {
$a.container.VAR does crud($arg);
}
class Foo {
has $.bar is rw;
# Provide an extra nested information
has $.baz is rw is crud(True);
}
By reading and adapting some example code, I managed to get something that seems to do what I want. Here is a snippet with test case.
When I instantiate a new Foo object and set the $.bar attribute (that is not crud), it looks like that:
.Foo #0
├ $.bar is rw = 123456789
└ $.baz is rw = .Scalar+{crud} #1
└ $.crud +{crud} = True
What I understand from this is that the $.baz attribute got what I call a meta-attribute that is independent from its potential value.
It looks good to me (if I understood correctly what I did here and that my traits use is not a dirty hack). It is possible to reach $foo.baz.crud that is True. Though, I don't understand very well what .Scalar+{crud} means, and if I can set something there and how.
When I try to set the $.baz instance attribute, this error is returned:
Cannot modify an immutable Scalar+{crud} (Scalar+{crud}.new(crud => Bool::True))
in block <unit> at t/08-attribute-trait.t line 30
Note: This is the closest thing to a working solution I managed to get. I don't need different crud settings for different instances of instantiated Foo classes.
I never want to change the value of the boolean, in fact, once the object instantiated, just providing it to attributes with is crud. I am not even interested to pass a True or False value as an argument: if it would be possible to just set the boolean trait attribute to True by default, it would be enough. I didn't manage to do this though, like:
multi trait_mod:<is>(Attribute $a, :$crud!) {
# Something like this
$a.container.VAR does set-crud;
}
class Foo {
has $.bar is rw;
has $.baz is rw is crud;
}
Am I trying to do something impossible? How could I adapt this code to achieve this use case?
There are several things going on here. First of all, the signature of the trait_mod looks to be wrong. Secondly, there appears to be a bad interaction when the name of a trait is the same as an existing role. I believe this should be an NYI exception, but apparently it either goes wrong in parsing, or it goes wrong in trying to produce the error message.
Anyways, I think this is what you want:
role CRUD {}; # since CRUD is used as an acronym, I chose to use uppercase here
multi trait_mod:<is>(Attribute:D $a, :$crud!) { # note required named attribute!
$a.^mixin: CRUD if $crud; # mixin the CRUD role if a True value was given
}
class A {
has $.a is crud(False); # too bad "is !crud" is invalid syntax
has $.b is crud;
}
say "$_.name(): { $_ ~~ CRUD }" for A.^attributes; # $!a: False, $!b: True
Hope this helps.

Groovy - Set your own property of an Integer

I just started to learn Groovy and wondering if you can set your own property for an integer. For example,
def a = 34.5.plus(34.34)
def b = 5.64.minus(3.43)
def c = 12.64.multiply(33.43)
In the above there are certain methods like plus minus and multiply
What should I do if I want to define some of my own methods for integers like that.
I searched Google but couldn't find much about it.
Sure, you can just add methods to the metaClass of Integer.
Here's an example:
Integer.metaClass.zeds = { -> 'z' * delegate }
assert 3.zeds() == 'zzz'
You can also add methods to a single instance of integer should you wish to, ie:
Integer num = 4
num.metaClass.halved = { -> delegate / 2.0 }
assert num.halved() == 2.0
You can also add methods to classes via Extension Methods a good explanation of which can be found over here
It should be noted (as you originally tagged this question as Java) that obviously, Java code will have no knowledge of these things, as it doesn't know about the metaClass
Use groovy meta programming, this allows you to create dynamic method creation atruntime in the class that you want to place in .
bydefault if a method is not found methodmissing exception throws , this is where groovy allows you add method at runtime for more reference use the below comprehensive link
http://groovy-lang.org/metaprogramming.html
If this answer helps , dont forget to click answered.

Can I redefine String#length?

I'd like to re-implement a method of a Java class. For example, for "hi".length() to return 4. (How) Can I do that?
I know using SomeClass.metaClass I can get a reference to an existing method and define new (or overriding) method, but I can't seem to be able to do that for existing Java methods.
Using Groovy, you can replace any method (even those of final classes) with your own implementation. Method replacement in Groovy uses the meta-object protocol, not inheritance.
Here's the example you requested, i.e. how to make String.length() always return 4
// Redefine the method
String.metaClass.invokeMethod = { name, args ->
def metaMethod = delegate.metaClass.getMetaMethod(name, args)
def result = metaMethod.invoke(delegate, args)
name == 'length' ? 4 : result
}
// Test it
assert "i_do_not_have_4_chars".length() == 4
Seems like it could be possible by abusing String metaClass. But the attempt I've done so far in groovy console didn't led to the expected result :
def oldLength = String.metaClass.length
String.metaClass.length = { ->
return oldLength+10;
}
println "hi".length()
outputs the sad 2
I think you could take a look at Proxy MetaClass or Delegating metaClass.
If you did redefine it, it would only work in Groovy code. Groovy can't change the way Java code executes.
In Groovy, "hi".length() is roughly equivalent to this Java:
stringMetaClass.invokeMethod("hi","length");
Because Groovy doesn't actually call length directly, metaClass tricks work in Groovy code. But Java doesn't know about MetaClasses, so there is no way to make this work.
Although this question is very old I like to point out another way (at least for newer Groovy versions) .
The length() method in java.lang.String is implemented from java.lang.CharSequence interface. In order to reimplement the method using the String-metaClass you need to "override" the method in the metaClass of the interface first.
CharSequence.metaClass.length = { -> -1}
String.metaClass.length = { -> 4 }
assert "i_do_not_have_4_chars".length() == 4
The solution using String.metaClass.invokeMethod changes the behaviour of all String-methods and is problematic. For instance, simply invoking "asdf".size() leads to an exception on my setup.

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