test(survey): cover unset flow in acceptance tests

Add two acceptance tests to confirm the drop-omitempty fix lets users
actually clear nullable fields through the provider, not just at the wire
format level:

* TestSurvey_ClearNumericLimits — sets responses_limit, iteration_count,
  iteration_frequency_days, response_sampling_interval_type,
  response_sampling_interval, response_sampling_limit, then drops every
  one of them. State after step 2 must show the attributes as unset,
  which only happens if PostHog actually cleared the underlying columns
  (MapResponseToModel maps them straight from the GET response).
* TestSurvey_LinkAndUnlinkFlag — exercises the highest-stakes case:
  link a fresh posthog_feature_flag via linked_flag_id, then remove the
  attribute while keeping the flag resource around. The survey should
  report no linked flag. Pre-fix, this would silently keep the link
  because the nil pointer was omitted from the PATCH body.

linked_insight_id is intentionally not covered: the response struct
doesn't model linked_insight_id, so MapResponseToModel can't verify the
clear from state alone. Worth a follow-up that adds the field to
httpclient.Survey and a matching acceptance test.

Author: vdekrijger

testacc/survey_test.go

@@ -141,3 +141,179 @@ resource "posthog_survey" "test" {
 }
 `, name)
 }
+
+// TestSurvey_ClearNumericLimits verifies that removing the nullable numeric
+// attributes from config sends an explicit JSON null on PATCH, which PostHog
+// interprets as "clear this column", and that the resulting state reflects the
+// cleared values. Without the drop-omitempty fix, step 2 would still observe
+// the values from step 1 because the omitempty pointer would never be sent.
+func TestSurvey_ClearNumericLimits(t *testing.T) {
+	skipIfNotAcceptance(t)
+
+	rName := acctest.RandomWithPrefix("tf-survey")
+
+	resource.Test(t, resource.TestCase{
+		PreCheck:                 func() { testAccPreCheck(t) },
+		ProtoV6ProviderFactories: testAccProtoV6ProviderFactories,
+		CheckDestroy:             testAccCheckSurveyDestroy,
+		Steps: []resource.TestStep{
+			// Step 1: create with every nullable numeric field set so we have a
+			// non-trivial baseline to clear from.
+			{
+				Config: testAccSurveyAllNumericLimits(rName),
+				Check: resource.ComposeAggregateTestCheckFunc(
+					resource.TestCheckResourceAttr(testSurveyResourceName, "schedule", "recurring"),
+					resource.TestCheckResourceAttr(testSurveyResourceName, "responses_limit", "100"),
+					resource.TestCheckResourceAttr(testSurveyResourceName, "iteration_count", "3"),
+					resource.TestCheckResourceAttr(testSurveyResourceName, "iteration_frequency_days", "7"),
+					resource.TestCheckResourceAttr(testSurveyResourceName, "response_sampling_interval_type", "week"),
+					resource.TestCheckResourceAttr(testSurveyResourceName, "response_sampling_interval", "2"),
+					resource.TestCheckResourceAttr(testSurveyResourceName, "response_sampling_limit", "50"),
+				),
+			},
+			// Step 2: drop every nullable numeric field. State must show them as
+			// unset, which only happens if PostHog actually cleared the columns —
+			// MapResponseToModel reads them straight from the GET response.
+			{
+				Config: testAccSurveyNoNumericLimits(rName),
+				Check: resource.ComposeAggregateTestCheckFunc(
+					resource.TestCheckNoResourceAttr(testSurveyResourceName, "responses_limit"),
+					resource.TestCheckNoResourceAttr(testSurveyResourceName, "iteration_count"),
+					resource.TestCheckNoResourceAttr(testSurveyResourceName, "iteration_frequency_days"),
+					resource.TestCheckNoResourceAttr(testSurveyResourceName, "response_sampling_interval"),
+					resource.TestCheckNoResourceAttr(testSurveyResourceName, "response_sampling_limit"),
+				),
+			},
+		},
+	})
+}
+
+// TestSurvey_LinkAndUnlinkFlag is the most user-visible drop-omitempty case:
+// linking a feature flag, then removing the linked_flag_id and confirming the
+// survey is actually unlinked server-side (the API response no longer
+// includes a linked_flag, so int64ValueFromMapOrNull surfaces null).
+func TestSurvey_LinkAndUnlinkFlag(t *testing.T) {
+	skipIfNotAcceptance(t)
+
+	rName := acctest.RandomWithPrefix("tf-survey")
+
+	resource.Test(t, resource.TestCase{
+		PreCheck:                 func() { testAccPreCheck(t) },
+		ProtoV6ProviderFactories: testAccProtoV6ProviderFactories,
+		CheckDestroy:             testAccCheckSurveyDestroy,
+		Steps: []resource.TestStep{
+			// Step 1: survey linked to a fresh feature flag.
+			{
+				Config: testAccSurveyWithLinkedFlag(rName),
+				Check: resource.ComposeAggregateTestCheckFunc(
+					resource.TestCheckResourceAttrPair(
+						testSurveyResourceName, "linked_flag_id",
+						"posthog_feature_flag.test", "id",
+					),
+				),
+			},
+			// Step 2: remove linked_flag_id from the survey while keeping the
+			// flag resource around. The survey should report no linked flag.
+			{
+				Config: testAccSurveyWithoutLinkedFlag(rName),
+				Check: resource.ComposeAggregateTestCheckFunc(
+					resource.TestCheckNoResourceAttr(testSurveyResourceName, "linked_flag_id"),
+				),
+			},
+		},
+	})
+}
+
+func testAccSurveyAllNumericLimits(name string) string {
+	return fmt.Sprintf(`
+provider "posthog" {}
+
+resource "posthog_survey" "test" {
+  name                            = %q
+  type                            = "popover"
+  schedule                        = "recurring"
+  responses_limit                 = 100
+  iteration_count                 = 3
+  iteration_frequency_days        = 7
+  response_sampling_interval_type = "week"
+  response_sampling_interval      = 2
+  response_sampling_limit         = 50
+
+  questions_json = jsonencode([
+    {
+      type     = "open"
+      question = "How satisfied are you?"
+    }
+  ])
+}
+`, name)
+}
+
+func testAccSurveyNoNumericLimits(name string) string {
+	return fmt.Sprintf(`
+provider "posthog" {}
+
+resource "posthog_survey" "test" {
+  name = %q
+  type = "popover"
+
+  questions_json = jsonencode([
+    {
+      type     = "open"
+      question = "How satisfied are you?"
+    }
+  ])
+}
+`, name)
+}
+
+func testAccSurveyWithLinkedFlag(name string) string {
+	return fmt.Sprintf(`
+provider "posthog" {}
+
+resource "posthog_feature_flag" "test" {
+  key                = %[1]q
+  name               = "Test flag for survey link"
+  active             = true
+  rollout_percentage = 100
+}
+
+resource "posthog_survey" "test" {
+  name           = %[1]q
+  type           = "popover"
+  linked_flag_id = posthog_feature_flag.test.id
+
+  questions_json = jsonencode([
+    {
+      type     = "open"
+      question = "How satisfied are you?"
+    }
+  ])
+}
+`, name)
+}
+
+func testAccSurveyWithoutLinkedFlag(name string) string {
+	return fmt.Sprintf(`
+provider "posthog" {}
+
+resource "posthog_feature_flag" "test" {
+  key                = %[1]q
+  name               = "Test flag for survey link"
+  active             = true
+  rollout_percentage = 100
+}
+
+resource "posthog_survey" "test" {
+  name = %[1]q
+  type = "popover"
+
+  questions_json = jsonencode([
+    {
+      type     = "open"
+      question = "How satisfied are you?"
+    }
+  ])
+}
+`, name)
+}