fix arg tests

Author: SteveL-MSFT

dsc/src/util.rs

@@ -425,8 +425,8 @@ pub fn get_input(input: &Option<String>, stdin: &Option<String>, path: &Option<S
     };
 
     if value.trim().is_empty() {
-        debug!("Provided input is empty");
-        return String::new();
+        error!("Provided input is empty");
+        exit(EXIT_INVALID_INPUT);
     }
 
     match parse_input_to_json(&value) {

dsc/tests/dsc_args.tests.ps1

@@ -186,22 +186,22 @@ resources:
         '' | dsc resource set -r Microsoft/OSInfo 2> $TestDrive/error.txt
         $err = Get-Content $testdrive/error.txt -Raw
         $err.Length | Should -Not -Be 0
-        $LASTEXITCODE | Should -Be 1
+        $LASTEXITCODE | Should -Be 4
     }
 
     It 'input cannot be empty if neither stdin or path is provided' {
         dsc resource set -r Microsoft/OSInfo --input " " 2> $TestDrive/error.txt
         $err = Get-Content $testdrive/error.txt -Raw
         $err.Length | Should -Not -Be 0
-        $LASTEXITCODE | Should -Be 1
+        $LASTEXITCODE | Should -Be 4
     }
 
     It 'path contents cannot be empty if neither stdin or input is provided' {
         Set-Content -Path $TestDrive/empty.yaml -Value " "
         dsc resource set -r Microsoft/OSInfo --path $TestDrive/empty.yaml 2> $TestDrive/error.txt
         $err = Get-Content $testdrive/error.txt -Raw
         $err.Length | Should -Not -Be 0
-        $LASTEXITCODE | Should -Be 1
+        $LASTEXITCODE | Should -Be 4
     }
 
     It 'document cannot be empty if neither stdin or path is provided' {