asears
commented
4 years ago Still working through the idiosyncracies of v5 myself and would also like some clarity on scoping in Pester 5. Have seen some odd behaviour when mocking things that Pester uses internally. (Set-TraceLevel for example)
I think the main issue is function Get-Foo() needs to be wrapped in Before block.
Mocks are scoped based on their placement Mocks are no longer effective in the whole Describe / Context in which they were placed. Instead they will defualt to the block in which they were placed.
Here's a working example, including new Should-Invoke syntax. I added the function code within BeforeAll, also works in BeforeEach.
Describe 'Example' {
BeforeAll {
function Get-Foo() {}
Mock Get-Foo -Verifiable {}
}
Context 'BeforeAll' {
BeforeAll {
function Get-Foo() {}
Mock Get-Foo -Verifiable {}
}
It "Doesn't work?" {
Get-Foo
Should -Invoke Get-Foo -Times 1 -Exactly
}
}
Context 'BeforeEach' {
BeforeEach {
Get-Foo
}
It 'Does work' {
Should -Invoke Get-Foo -Times 1 -Exactly
}
}
Describe 'It' {
It 'Also works' {
Get-Foo
Should -Invoke Get-Foo -Times 1 -Exactly
}
}
}diff --git b/my.tests.ps1 a/my.tests.ps1
index 2ec38a7..9ad915f 100644
--- b/my.tests.ps1
+++ a/my.tests.ps1
@@ -1,15 +1,17 @@
-function Get-Foo() {}
Describe 'Example' {
- BeforeEach {
+ BeforeAll {
+ function Get-Foo() {}
Mock Get-Foo -Verifiable {}
}
Context 'BeforeAll' {
BeforeAll {
- Get-Foo
+ function Get-Foo() {}
+ Mock Get-Foo -Verifiable {}
}
It "Doesn't work?" {
- Assert-MockCalled Get-Foo -Times 1 -Exactly
+ Get-Foo
+ Should -Invoke Get-Foo -Times 1 -Exactly
}
}
Context 'BeforeEach' {
@@ -17,13 +19,13 @@ Describe 'Example' {
Get-Foo
}
It 'Does work' {
- Assert-MockCalled Get-Foo -Times 1 -Exactly
+ Should -Invoke Get-Foo -Times 1 -Exactly
}
}
Describe 'It' {
It 'Also works' {
Get-Foo
- Assert-MockCalled Get-Foo -Times 1 -Exactly
+ Should -Invoke Get-Foo -Times 1 -Exactly
}
}
}
BeforeAll: Defines a series of steps to perform at the beginning of the current Context or Describe block. BeforeEach: Defines a series of steps to perform at the beginning of every It block within the current Context or Describe block. Context: Provides logical grouping of It blocks within a single Describe block. Describe: Creates a logical group of tests. Should: Should is a keyword what is used to define an assertion inside It block.
Should documentation is missing new -Invoke syntax. https://pester.dev/docs/commands/Should Probably need an issue for that.
From Converting tests to pester 5
Code inside a Describe- or Context-block should be inside a It-, Before-, or After-block. The exception to this is variables that contain test cases, those variables should be placed inside the Describe-block and before the It-block, but outside of the Before-blocks. they must be outside Before-blocks and It-blocks, but inside Describe- or Context-blocks.
From Community talk about Pester 5
| Pester v4 | Pester v5 |
|---|---|
| In Pester v4 the BeforeEach is executed in a scope above It, so variables defined in BeforeEach are not writable from It and not changed in AfterEach, this makes sharing data between the test and the teardown difficult. For example when you created a file in the test and want to remove it, or close a connection to a database etc. | In Pester v5 BeforeEach It and AfterEach all run in the same scope. |
| In Pester v4 the mock defined in the It block is defined on the containing Describe, so it leaks to the subsequest It blocks. This is a hurdle that everyone learning Pester faces. It also forces the test author to add unnecessary Context blocks when the mock should be "isolated" to one It block. | In Pester v5 the Mock is defined on the block that contains it. So putting it within It will define this mock for that It and putting it into BeforeAll will define it for the Describe/Context that contains it. |
| Should is the way to do assertions, yet in Pester v4 there are two notably different assertions, Assert-MockCalled and Assert-VerifiableMock | in Pester v5 these commands are deprecated and Should -Invoke and Should -InvokeVerifiable are newly available, and recommended to use. |
We can leverage the new PesterPreference / Configuration Object to get some additional details on what is going on. I have a setup script which configures the object's common properties. Here's one I toggle to show the details on what Pester's doing with mocks.
$PesterPreference = [PesterConfiguration]::Default
$PesterPreference.Debug.WriteDebugMessages = $true
jsmythsci
1. General summary of the issue
It seems that Mocks called within a
BeginAll{}block cannot be verified in an adjacent childIt{}block.Based on what I have read it seems like it should work but maybe I am missing something.
Here is sample code to illustrate what I mean:
2. Describe Your Environment
Pester version : 5.0.2 C:\Program Files\WindowsPowerShell\Modules\Pester\5.0.2\Pester.psd1 PowerShell version : 5.1.18362.752 OS version : Microsoft Windows NT 10.0.18363.0
3. Expected Behavior
The sample code should pass its test. Smallest sample that demonstrates the issue:
4.Current Behavior
The sample code returns the following error:
5. Possible Solution
6. Context
I am new to Pester and very new to v5. I ran across this while refactoring some tests that worked fine in v3.
I suspect that it is something that I just don't understand rather than an actual bug but I figured I would raise it since I can't find anything that seems to explain why it should work this way.