chore(terraform): refactor region overrides in mapping funcs (#872)

stackit/internal/core/core.go

@@ -6,6 +6,8 @@ import (
 	"net/http"
 	"strings"
 
+	"github.com/hashicorp/terraform-plugin-framework/types"
+
 	"github.com/hashicorp/terraform-plugin-framework/diag"
 	"github.com/hashicorp/terraform-plugin-log/tflog"
 )
@@ -61,6 +63,13 @@ func (pd *ProviderData) GetRegion() string {
 	return "eu01"
 }
 
+func (pd *ProviderData) GetRegionWithOverride(overrideRegion types.String) string {
+	if overrideRegion.IsUnknown() || overrideRegion.IsNull() {
+		return pd.GetRegion()
+	}
+	return overrideRegion.ValueString()
+}
+
 // DiagsToError Converts TF diagnostics' errors into an error with a human-readable description.
 // If there are no errors, the output is nil
 func DiagsToError(diags diag.Diagnostics) error {

stackit/internal/core/core_test.go

@@ -0,0 +1,100 @@
+package core
+
+import (
+	"testing"
+
+	"github.com/hashicorp/terraform-plugin-framework/types"
+)
+
+func TestProviderData_GetRegionWithOverride(t *testing.T) {
+	type args struct {
+		overrideRegion types.String
+	}
+	tests := []struct {
+		name         string
+		providerData *ProviderData
+		args         args
+		want         string
+	}{
+		{
+			name: "override region is null string",
+			providerData: &ProviderData{
+				DefaultRegion: "eu02",
+			},
+			args: args{
+				types.StringNull(),
+			},
+			want: "eu02",
+		},
+		{
+			name: "override region is unknown string",
+			providerData: &ProviderData{
+				DefaultRegion: "eu02",
+			},
+			args: args{
+				types.StringUnknown(),
+			},
+			want: "eu02",
+		},
+		{
+			name: "override region is set",
+			providerData: &ProviderData{
+				DefaultRegion: "eu02",
+			},
+			args: args{
+				types.StringValue("eu01"),
+			},
+			want: "eu01",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := tt.providerData.GetRegionWithOverride(tt.args.overrideRegion); got != tt.want {
+				t.Errorf("GetRegionWithOverride() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestProviderData_GetRegion(t *testing.T) {
+	tests := []struct {
+		name         string
+		providerData *ProviderData
+		want         string
+	}{
+		{
+			name: "default region is set",
+			providerData: &ProviderData{
+				DefaultRegion: "eu02",
+			},
+			want: "eu02",
+		},
+		{
+			name: "(legacy) region is set",
+			providerData: &ProviderData{
+				Region: "eu02",
+			},
+			want: "eu02",
+		},
+		{
+			name: "default region wins over (legacy) region",
+			providerData: &ProviderData{
+				DefaultRegion: "eu02",
+				Region:        "eu01",
+			},
+			want: "eu02",
+		},
+		{
+			name:         "final fallback - neither region (legacy) nor default region is set",
+			providerData: &ProviderData{},
+			want:         "eu01",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := tt.providerData.GetRegion(); got != tt.want {
+				t.Errorf("GetRegion() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}