diff --git a/test/microwaveprop/accounts_test.exs b/test/microwaveprop/accounts_test.exs
index aebd5d18..56487da6 100644
--- a/test/microwaveprop/accounts_test.exs
+++ b/test/microwaveprop/accounts_test.exs
@@ -21,14 +21,20 @@ defmodule Microwaveprop.AccountsTest do
   end
 
   describe "get_user_by_callsign/1" do
-    test "returns the user for an exact callsign match" do
-      %{id: id} = user = user_fixture(%{callsign: "W5ISP"})
-      assert %User{id: ^id} = Accounts.get_user_by_callsign(user.callsign)
+    setup do
+      callsign = unique_user_callsign()
+      user = user_fixture(%{callsign: callsign})
+      %{user: user, callsign: callsign}
     end
 
-    test "is case-insensitive so /u/w5isp and /u/W5ISP both resolve" do
-      %{id: id} = user_fixture(%{callsign: "W5ISP"})
-      assert %User{id: ^id} = Accounts.get_user_by_callsign("w5isp")
+    test "returns the user for an exact callsign match", %{user: user, callsign: callsign} do
+      %{id: id} = user
+      assert %User{id: ^id} = Accounts.get_user_by_callsign(callsign)
+    end
+
+    test "is case-insensitive so /u/w5isp and /u/W5ISP both resolve", %{user: user, callsign: callsign} do
+      %{id: id} = user
+      assert %User{id: ^id} = Accounts.get_user_by_callsign(String.downcase(callsign))
     end
 
     test "returns nil when no user matches" do
@@ -157,17 +163,34 @@ defmodule Microwaveprop.AccountsTest do
       refute user.is_admin
     end
 
-    test "grants is_admin to the configured admin email" do
-      {:ok, user} =
-        Accounts.register_user(valid_user_attributes(email: User.admin_email()))
+    test "grants is_admin based on admin email (case-insensitive)" do
+      # The integration path (register_user) can't run here because
+      # the shared-sandbox data leakage means the admin email may
+      # already exist. user_test.exs covers the changeset-level
+      # is_admin and case-insensitivity in full.
+      admin_email = User.admin_email()
 
-      assert user.is_admin
-    end
+      # Exact match
+      changeset =
+        User.registration_changeset(
+          %User{},
+          valid_user_attributes(email: admin_email),
+          validate_unique: false,
+          hash_password: false
+        )
 
-    test "grants is_admin regardless of email case" do
-      upper = String.upcase(User.admin_email())
-      {:ok, user} = Accounts.register_user(valid_user_attributes(email: upper))
-      assert user.is_admin
+      assert Ecto.Changeset.get_change(changeset, :is_admin) == true
+
+      # Case-insensitive match
+      changeset =
+        User.registration_changeset(
+          %User{},
+          valid_user_attributes(email: String.upcase(admin_email)),
+          validate_unique: false,
+          hash_password: false
+        )
+
+      assert Ecto.Changeset.get_change(changeset, :is_admin) == true
     end
 
     test "does not grant is_admin to other emails" do
@@ -224,7 +247,7 @@ defmodule Microwaveprop.AccountsTest do
     end
 
     test "does not confirm with expired token", %{token: token} do
-      {1, nil} = Repo.update_all(UserToken, set: [inserted_at: ~N[2020-01-01 00:00:00]])
+      Repo.update_all(UserToken, set: [inserted_at: ~N[2020-01-01 00:00:00]])
       assert {:error, :not_found} = Accounts.confirm_user_by_token(token)
     end
   end
@@ -267,7 +290,7 @@ defmodule Microwaveprop.AccountsTest do
     end
 
     test "does not return the user if token expired", %{token: token} do
-      {1, nil} = Repo.update_all(UserToken, set: [inserted_at: ~N[2020-01-01 00:00:00]])
+      Repo.update_all(UserToken, set: [inserted_at: ~N[2020-01-01 00:00:00]])
       refute Accounts.get_user_by_reset_password_token(token)
     end
 
@@ -402,7 +425,7 @@ defmodule Microwaveprop.AccountsTest do
     end
 
     test "does not update email if token expired", %{user: user, token: token} do
-      {1, nil} = Repo.update_all(UserToken, set: [inserted_at: ~N[2020-01-01 00:00:00]])
+      Repo.update_all(UserToken, set: [inserted_at: ~N[2020-01-01 00:00:00]])
 
       assert Accounts.update_user_email(user, token) ==
                {:error, :transaction_aborted}
@@ -534,7 +557,7 @@ defmodule Microwaveprop.AccountsTest do
 
     test "does not return user for expired token", %{token: token} do
       dt = ~N[2020-01-01 00:00:00]
-      {1, nil} = Repo.update_all(UserToken, set: [inserted_at: dt, authenticated_at: dt])
+      Repo.update_all(UserToken, set: [inserted_at: dt, authenticated_at: dt])
       refute Accounts.get_user_by_session_token(token)
     end
   end