Fix failing matrix-generator tests

[konrad-jamrozik]

A bug discovered while working on:

• Fix broken relative paths in matrix-generator tests and samples + make the tests runnable by common-tests/ci.yml. #5095

Located in:

azure-sdk-tools\eng\common-tests\matrix-generator\tests\job-matrix-functions.modification.tests.ps1

The bug is described in the header comment in the snippet below.

Snippet:

# This test is currently disabled (it doesn't have "UnitTest" tag) as it fails 
# in test "Should generate a sparse matrix where the entire base matrix is imported" on line:
#
#   $matrix = GenerateMatrix $importConfig "sparse"
#
# with message:
# 
#   ParameterBindingArgumentTransformationException: Cannot process argument transformation on parameter 'parameters'. Cannot convert the "System.Collections.Hashtable" value of type "System.Collections.Hashtable" to type "MatrixParameter".
#
# See full build failure:
# https://dev.azure.com/azure-sdk/internal/_build/results?buildId=2102328&view=logs&j=375fdae1-accf-5db0-5fc3-af258c8525cc&t=9e9d0eca-bdb6-593f-47d7-63cf69095eca&l=22
#
# Issue to track:
# https://github.com/Azure/azure-sdk-tools/issues/5098
Describe "Platform Matrix Import" -Tag "import" {
    It "Should generate a sparse matrix where the entire base matrix is imported" {
        $matrixJson = @'
{
    "matrix": {
        "$IMPORT": "./matrix-generator/tests/test-import-matrix.json"
    },
    "include": [
        {
            "fooinclude": "fooinclude"
        }
    ]
}
'@

        $expectedMatrix = @'
[
  {
    "parameters": { "Foo": "foo1", "Bar": "bar1" },
    "name": "foo1_bar1"
  },
  {
    "parameters": { "Foo": "foo2", "Bar": "bar2" },
    "name": "foo2_bar2"
  },
  {
    "parameters": { "Baz": "importedBaz" },
    "name": "importedBazName"
  },
  {
    "parameters": { "fooinclude": "fooinclude" },
    "name": "fooinclude"
  },
]
'@

        $importConfig = GetMatrixConfigFromJson $matrixJson
        $matrix = GenerateMatrix $importConfig "sparse"
        $expected = $expectedMatrix | ConvertFrom-Json -AsHashtable

        $matrix.Length | Should -Be 4
        CompareMatrices $matrix $expected
    }