Mercury integration (#723)

* Initial mercury impl

* FIX both mercury and generator class

* Finish mercury integration and provider generator

* Fix schema

* Fix linter and tags

* Update routes.rb

* Avoid schema drift

---------

Signed-off-by: soky srm <sokysrm@gmail.com>
Co-authored-by: Juan José Mata <juanjo.mata@gmail.com>

test/models/provider/mercury_adapter_test.rb

@@ -0,0 +1,38 @@
+require "test_helper"
+
+class Provider::MercuryAdapterTest < ActiveSupport::TestCase
+  test "supports Depository accounts" do
+    assert_includes Provider::MercuryAdapter.supported_account_types, "Depository"
+  end
+
+  test "does not support Investment accounts" do
+    assert_not_includes Provider::MercuryAdapter.supported_account_types, "Investment"
+  end
+
+  test "returns connection configs for any family" do
+    # Mercury is a per-family provider - any family can connect
+    family = families(:dylan_family)
+    configs = Provider::MercuryAdapter.connection_configs(family: family)
+
+    assert_equal 1, configs.length
+    assert_equal "mercury", configs.first[:key]
+    assert_equal "Mercury", configs.first[:name]
+    assert configs.first[:can_connect]
+  end
+
+  test "build_provider returns nil when family is nil" do
+    assert_nil Provider::MercuryAdapter.build_provider(family: nil)
+  end
+
+  test "build_provider returns nil when family has no mercury items" do
+    family = families(:empty)
+    assert_nil Provider::MercuryAdapter.build_provider(family: family)
+  end
+
+  test "build_provider returns Mercury provider when credentials configured" do
+    family = families(:dylan_family)
+    provider = Provider::MercuryAdapter.build_provider(family: family)
+
+    assert_instance_of Provider::Mercury, provider
+  end
+end