Add new pester test for Select-Object cmdlet

src/pester-tests/Test-Select-Object.Tests.ps1

@@ -0,0 +1,94 @@
+. ../../../src/pester-tests/Test-Mocks.ps1
+
+Describe "Select-Object" {
+    BeforeEach {
+        $o=GetFileMock
+        $TestLength = 3
+    }
+
+    It "Handle piped input without error" {
+        { $o | Test-Path } | Should Not Throw
+    } 
+
+    It "-inputObject parameter should treats object as a single object" {
+        $(Select-Object -inputObject $o -last $TestLength).Length | Should Be $o.Length
+    }
+
+    It "Should be able to use the alias" {
+        { $o | select } | Should Not Throw
+        { $o | select } | Should Not BeNullOrEmpty
+    }
+
+    It "-First parameter should return correct object" {
+        $r = $o | Select-Object -First $TestLength
+        $r.Length | Should Be $TestLength
+        for ($i=0; $i -lt $TestLength; $i++)
+        {
+            $r[$i].Name | Should Be $o[$i].Name
+        }
+    }
+
+    It "-Last parameter should return correct object" {
+        $r = $o | Select-Object -Last $TestLength
+        $r.Length | Should Be $TestLength
+        for ($i=0; $i -lt $TestLength; $i++)
+        {
+            $r[$i].Name | Should Be $o[$o.Length - $TestLength + $i].Name
+        }
+    }
+
+    It "-Unique parameter should work correctly" {
+        ("a","b","c","a","a","a" | Select-Object -Unique).Length | Should Be 3
+    }
+
+    It "-Skip parameter should return correct object" {
+        $r = $o | Select-Object -Skip $TestLength
+        $r.Length | Should Be ($o.Length - $TestLength)
+        for ($i=0; $i -lt $TestLength; $i++)
+        {
+            $r[$i].Name | Should Be $o[$TestLength + $i].Name
+        }
+    }
+
+    It "-Property parameter should return an object with selected columns" {
+        $r = $o | Select-Object -Property Name, Size
+        $r.Length | Should Be $o.Length
+        $r[0].Name | Should Be $o[0].Name
+        $r[0].Size | Should Be $o[0].Size
+        $r[0].Mode | Should BeNullOrEmpty
+    }
+
+    It "Select-Object should send output to pipe properly" {
+        {$o | Select-Object -Unique | pipelineConsume} | Should Not Throw
+    } 
+
+    It "-Index parameter should select array indices" {
+        $firstIndex = 2
+        $secondIndex = 4
+        $r = $o | Select-Object -Index $firstIndex, $secondIndex
+        $r[0].Name | Should Be $o[$firstIndex].Name
+        $r[1].Name | Should Be $o[$secondIndex].Name
+    }
+
+    # Note that these two tests will modify original values of $o
+
+    It "-First option does not wait when used without -Wait option" {
+        $orig1 = $o[0].Size
+        $orig2 = $o[$TestLength].Size
+        $r = $o | addOne | Select-Object -First $TestLength
+        $r[0].Size | Should Be ($orig1 + 1)
+        $o[0].Size | Should Be ($orig1 + 1)
+        $o[$TestLength].Size | Should Be $orig2
+    }
+
+    It "-First option does wait when used with -Wait option" {
+        $orig1 = $o[0].Size
+        $orig2 = $o[$TestLength].Size
+        $r = $o | addOne | Select-Object -First $TestLength -Wait
+        $r[0].Size | Should Be ($orig1 + 1)
+        $o[0].Size | Should Be ($orig1 + 1)
+        $o[$TestLength].Size | Should Be ($orig2 + 1)
+    }
+}
+
+