diff --git a/src/pester-tests/Test-Select-String.Tests.ps1 b/src/pester-tests/Test-Select-String.Tests.ps1
new file mode 100644
index 000000000..54a21ac72
--- /dev/null
+++ b/src/pester-tests/Test-Select-String.Tests.ps1
@@ -0,0 +1,173 @@
+Describe "Test-Select-String" {
+    Context "String actions" {
+    $testinputone = "hello","Hello","goodbye"
+    $testinputtwo = "hello","Hello"
+
+        it "Should be called without errors" {
+            { $testinputone | Select-String -Pattern "hello" } | Should Not Throw
+        }
+
+        it "Should be called without error using the sls alias" {
+            { $testinputone | sls -Pattern "hello" } | Should Not Throw
+        }
+
+        it "Should return an array data type when multiple matches are found" {
+            ( $testinputtwo | Select-String -Pattern "hello").gettype().basetype | Should Be Array
+        }
+
+        it "Should return the same result for the alias sls and Select-String " { 
+            $firstMatch = $testinputone | Select-String -Pattern "hello"
+            $secondMatch = $testinputone | sls -Pattern "hello"
+
+            $equal = @(compare-object $firstMatch $secondMatch).Length -eq 0
+            $equal | Should Be True
+        }
+
+        it "Should return an object type when one match is found" {
+            ( $testinputtwo | Select-String -Pattern "hello" -CaseSensitive).gettype().basetype | Should Be System.Object
+        }
+
+        it "Should return matchinfo type" {
+            ( $testinputtwo | Select-String -Pattern "hello" -CaseSensitive).gettype().name | Should Be MatchInfo
+        }
+
+        it "Should be called without an error using ca for casesensitive " {
+            {$testinputone | Select-String -Pattern "hello" -ca } | Should Not Throw
+        }
+
+        it "Should use the ca alias for casesenstive" {
+            $firstMatch = $testinputtwo  | Select-String -Pattern "hello" -CaseSensitive
+            $secondMatch = $testinputtwo | Select-String -Pattern "hello" -ca
+
+            $equal = @(Compare-Object $firstMatch $secondMatch).Length -eq 0
+            $equal | Should Be True
+        }
+
+        it "Should only return the case sensitive match when the casesensitive switch is used" {
+             $testinputtwo | Select-String -Pattern "hello" -CaseSensitive | Should Be "hello"
+        }
+
+        it "Should accept a collection of strings from the input object" {
+            { Select-String -InputObject "some stuff", "other stuff" -Pattern "other" } | Should Not Throw
+        }
+
+        it "Should return system.object when the input object switch is used on a collection" {
+            ( Select-String -InputObject "some stuff", "other stuff" -pattern "other" ).gettype().basetype | Should Be System.Object
+        }
+
+        it "Should return null or empty when the input object switch is used on a collection and the pattern does not exist" {
+            Select-String -InputObject "some stuff", "other stuff" -Pattern "neither" | Should BeNullOrEmpty
+        }
+
+        it "Should return a bool type when the quiet switch is used" {
+            ($testinputtwo | Select-String -Quiet "hello" -CaseSensitive).gettype() | Should Be Bool
+        }
+
+        it "Should be true when select string returns a positive result when the quiet switch is used" {
+            ($testinputtwo | Select-String -Quiet "hello" -CaseSensitive) | Should Be $True
+        }
+
+        it "Should be empty when select string does not return a result when the quiet switch is used" {
+            $testinputtwo | Select-String -Quiet "goodbye"  | Should BeNullOrEmpty
+        }
+
+        it "Should return an array of non matching strings when the switch of NotMatch is used and the string do not match" {
+            $testinputone | Select-String -Pattern "goodbye" -NotMatch | Should Be "hello", "hello"
+        }
+
+        it "Should return the same as NotMatch" {
+            $firstMatch = $testinputone | Select-String -pattern "goodbye" -NotMatch
+            $secondMatch = $testinputone | Select-String -pattern "goodbye" -n
+
+            $equal = @(Compare-Object $firstMatch $secondMatch).Length -eq 0
+            $equal | Should Be True
+        }
+    }
+
+    Context "Filesytem actions" {
+        $testInputFile =  "/tmp/testfile1.txt"
+        BeforeEach {
+            New-Item $testInputFile -Itemtype "file" -Force -Value "This is a text string, and another string`nThis is the second line`nThis is the third line`nThis is the fourth line`nNo matches"
+        }
+
+        It "Should return an object when a match is found is the file on only one line" {
+            (Select-String $testInputFile -Pattern "string").GetType().BaseType | Should be System.Object
+        }
+
+        It "Should return an array when a match is found is the file on several lines" {
+            (Select-String $testInputFile -Pattern "in").GetType().BaseType | Should be array
+            (Select-String $testInputFile -Pattern "in")[0].GetType().Name  | Should Be MatchInfo
+        }
+
+        It "Should return the name of the file and the string that 'string' is found if there is only one lines that has a match" {
+            $expected = $testInputFile + ":1:This is a text string, and another string"
+
+            Select-String $testInputFile -Pattern "string" | Should Be $expected 
+        }
+
+        It "Should return all strings where 'second' is found in testfile1 if there is only one lines that has a match" {
+            $expected = $testInputFile + ":2:This is the second line"
+
+            Select-String $testInputFile  -Pattern "second"| Should Be $expected
+        }
+
+        It "Should return all strings where 'in' is found in testfile1 pattern switch is not required" {
+            $expected1 = "This is a text string, and another string"
+            $expected2 = "This is the second line"
+            $expected3 = "This is the third line"
+            $expected4 = "This is the fourth line"
+
+            (Select-String in $testInputFile)[0].Line | Should Be $expected1
+            (Select-String in $testInputFile)[1].Line | Should Be $expected2
+            (Select-String in $testInputFile)[2].Line | Should Be $expected3
+            (Select-String in $testInputFile)[3].Line | Should Be $expected4
+            (Select-String in $testInputFile)[4].Line | Should BeNullOrEmpty
+        }
+
+        It "Should return empty because 'for' is not  found in testfile1 " {
+            Select-String for $testInputFile | Should BeNullOrEmpty
+        }
+
+        It "Should return the third line in testfile1 and the lines above and below it " {
+            $expectedLine       = "testfile1.txt:2:This is the second line"
+            $expectedLineBefore = "testfile1.txt:3:This is the third line"
+            $expectedLineAfter  = "/tmp/testfile1.txt:4:This is the fourth line"
+
+            Select-String third $testInputFile -Context 1 | Should Match $expectedLine
+            Select-String third $testInputFile -Context 1 | Should Match $expectedLineBefore 
+            Select-String third $testInputFile -Context 1 | Should Match $expectedLineAfter 
+        }
+
+        It "Should return the number of matches for 'is' in textfile1 " {
+            (Select-String is $testInputFile -CaseSensitive).count| Should Be 4
+        }
+
+        It "Should return the third line in testfile1 when a relative path is used" {
+            $expected  = "/tmp/testfile1.txt:3:This is the third line"
+
+            Select-String third /tmp/../tmp/testfile1.txt  | Should Match $expected
+        }
+
+        It "Should return the fourth line in testfile1 when a relative path is used" {
+            $testDirectory = "/tmp/"
+            $expected      = "/tmp/testfile1.txt:5:No matches"
+
+            pushd $testDirectory
+
+            Select-String matches $testDirectory/testfile1.txt  | Should Match $expected
+            popd
+        }
+
+        It "Should return the fourth line in testfile1 when a regular expression is used" {
+            $expected  = "/tmp/testfile1.txt:5:No matches"
+
+            Select-String 'matc*' $testInputFile -CaseSensitive | Should Match $expected
+        }
+
+        It "Should return the fourth line in testfile1 when a regular expression is used, using the alias for casesensitive" {
+            $expected  = "/tmp/testfile1.txt:5:No matches"
+
+            Select-String 'matc*' $testInputFile -ca | Should Match $expected
+        }
+    }
+}