bug: added basic test to detect stack files

Author: denis256

test/fixtures/regressions/multiple-stacks/live/appv2.terragrunt.stack.hcl

@@ -0,0 +1,10 @@
+
+unit "unit3" {
+  source = "../units/template"
+  path   = "unit3"
+}
+
+unit "unit4" {
+  source = "../units/template"
+  path   = "unit4"
+}

test/fixtures/regressions/multiple-stacks/live/terragrunt.stack.hcl

@@ -0,0 +1,9 @@
+unit "unit1" {
+  source = "../units/template"
+  path   = "unit1"
+}
+
+unit "unit2" {
+  source = "../units/template"
+  path   = "unit2"
+}

test/fixtures/regressions/multiple-stacks/units/template/main.tf

@@ -19,6 +19,7 @@ const (
 	testFixtureDependencyEmptyConfigPath = "fixtures/regressions/dependency-empty-config-path"
 	testFixtureParsingDeprecated         = "fixtures/parsing/exposed-include-with-deprecated-inputs"
 	testFixtureSensitiveValues           = "fixtures/regressions/sensitive-values"
+	testFixtureStackDetection            = "fixtures/regressions/multiple-stacks"
 )
 
 func TestNoAutoInit(t *testing.T) {
@@ -371,3 +372,23 @@ func TestSensitiveValues(t *testing.T) {
 	assert.Equal(t, "25", passwordLengthStr,
 		"Password length should match dev password")
 }
+
+func TestMultipleStacksDetection(t *testing.T) {
+	t.Parallel()
+
+	helpers.CleanupTerraformFolder(t, testFixtureStackDetection)
+	tmpEnvPath := helpers.CopyEnvironment(t, testFixtureStackDetection)
+	rootPath := util.JoinPath(tmpEnvPath, testFixtureStackDetection, "live")
+
+	_, stderr, err := helpers.RunTerragruntCommandWithOutput(t, "terragrunt stack generate --working-dir "+rootPath)
+
+	require.NoError(t, err)
+
+	assert.Contains(t, stderr, "terragrunt.stack.hcl")
+	assert.Contains(t, stderr, "unit1")
+	assert.Contains(t, stderr, "unit2")
+
+	assert.NotContains(t, stderr, "appv2.terragrunt.stack.hcl")
+	assert.NotContains(t, stderr, "unit4")
+	assert.NotContains(t, stderr, "unit3")
+}