oneshot

config/test.exs

@@ -5,13 +5,46 @@ import Config
 # The MIX_TEST_PARTITION environment variable can be used
 # to provide built-in test partitioning in CI environment.
 # Run `mix help test` for more information.
-config :rsh26pool, Rsh26pool.Repo,
-  username: "postgres",
-  password: "postgres",
-  hostname: "localhost",
-  database: "rsh26pool_test#{System.get_env("MIX_TEST_PARTITION")}",
-  pool: Ecto.Adapters.SQL.Sandbox,
-  pool_size: System.schedulers_online() * 2
+#
+# When DATABASE_URL is set (see .env) we reuse its server but connect to a
+# dedicated "<db>_test" database so tests never touch development data.
+partition = System.get_env("MIX_TEST_PARTITION")
+
+if url = System.get_env("DATABASE_URL") do
+  uri = URI.parse(url)
+
+  {username, password} =
+    case uri.userinfo do
+      nil ->
+        {"postgres", "postgres"}
+
+      info ->
+        case String.split(info, ":", parts: 2) do
+          [u, p] -> {u, p}
+          [u] -> {u, nil}
+        end
+    end
+
+  base = uri.path |> to_string() |> String.trim_leading("/")
+  base = if base == "", do: "rsh26pool", else: base
+
+  config :rsh26pool, Rsh26pool.Repo,
+    username: username,
+    password: password,
+    hostname: uri.host || "localhost",
+    port: uri.port || 5432,
+    database: "#{base}_test#{partition}",
+    pool: Ecto.Adapters.SQL.Sandbox,
+    pool_size: System.schedulers_online() * 2
+else
+  config :rsh26pool, Rsh26pool.Repo,
+    username: "postgres",
+    password: "postgres",
+    hostname: "localhost",
+    database: "rsh26pool_test#{partition}",
+    pool: Ecto.Adapters.SQL.Sandbox,
+    pool_size: System.schedulers_online() * 2
+end
 
 # We don't run a server during test. If one is required,
 # you can enable the server option below.