Fail fast on errors in powershell TTP steps (#518)

Summary:

Set ErrorActionPreference variable as first thing when executing the powershell TTPs

Resolves #517
Brings parity with bash fail-fast logic introduced in #406

Differential Revision: D65080213

pkg/blocks/executor.go

@@ -96,7 +96,7 @@ func (e *ScriptExecutor) Execute(ctx context.Context, execCtx TTPExecutionContex
 	body := expandedInlines[0]
 	if e.Name == ExecutorPowershellOnLinux || e.Name == ExecutorPowershell {
 		// Wrap the PowerShell command in a script block
-		body = fmt.Sprintf("&{%s}\n\n", body)
+		body = fmt.Sprintf("$ErrorActionPreference = 'Stop' ; &{%s}\n\n", body)
 	}
 
 	// expand variables in environment

pkg/blocks/executor_test.go

@@ -0,0 +1,34 @@
+package blocks
+
+import (
+	"context"
+	"testing"
+)
+
+func TestBashExecutor_Echo_Success(t *testing.T) {
+	emptyEnvironment := map[string]string{}
+	execCtx := TTPExecutionContext{Vars: &TTPExecutionVars{}}
+	executor := NewExecutor("bash", "echo success", "", []string{}, emptyEnvironment)
+
+	result, err := executor.Execute(context.Background(), execCtx)
+	if err != nil {
+		t.Fatalf("expected no error, got %v", err)
+	}
+	if result.Stdout != "success\n" {
+		t.Fatalf("expected output 'success\\n', got %#v", result.Stdout)
+	}
+}
+
+func TestBashExecutor_False_FailFast(t *testing.T) {
+	emptyEnvironment := map[string]string{}
+	execCtx := TTPExecutionContext{Vars: &TTPExecutionVars{}}
+	executor := NewExecutor("bash", "false; echo success", "", []string{}, emptyEnvironment)
+
+	result, err := executor.Execute(context.Background(), execCtx)
+	if err == nil {
+		t.Fatalf("expected error, got result %#v", result)
+	}
+	if err.Error() != "exit status 1" {
+		t.Fatalf("expected error 'exit status 1', got %#v", err.Error())
+	}
+}