CSV Transaction Imports (#708)

Introduces a basic CSV import module for bulk-importing account transactions.

Changes include:

- User can load a CSV
- User can configure the column mappings for a CSV
- Imported CSV shows invalid cells
- User can clean up their data directly in the UI
- User can see a preview of the import rows and confirm import
- Layout refactor + Import nav stepper
- System test stability improvements

test/models/import/csv_test.rb

@@ -0,0 +1,87 @@
+require "test_helper"
+
+class Import::CsvTest < ActiveSupport::TestCase
+  include ImportTestHelper
+
+  setup do
+    @csv = Import::Csv.new(valid_csv_str)
+  end
+
+  test "cannot define validator for non-existent header" do
+    assert_raises do
+      @csv.define_validator "invalid", method(:validate_iso_date)
+    end
+  end
+
+  test "csv with no validators is valid" do
+    assert @csv.cell_valid?(0, 0)
+    assert @csv.valid?
+  end
+
+  test "valid csv values" do
+    @csv.define_validator "date", method(:validate_iso_date)
+
+    assert_equal "2024-01-01", @csv.table[0][0]
+    assert @csv.cell_valid?(0, 0)
+    assert @csv.valid?
+  end
+
+  test "invalid csv values" do
+    invalid_csv = Import::Csv.new valid_csv_with_invalid_values
+
+    invalid_csv.define_validator "date", method(:validate_iso_date)
+
+    assert_equal "invalid_date", invalid_csv.table[0][0]
+    assert_not invalid_csv.cell_valid?(0, 0)
+    assert_not invalid_csv.valid?
+  end
+
+  test "updating a cell returns a copy of the original csv" do
+    original_date = "2024-01-01"
+    new_date = "2024-01-01"
+
+    assert_equal original_date, @csv.table[0][0]
+    updated = @csv.update_cell(0, 0, new_date)
+
+    assert_equal original_date, @csv.table[0][0]
+    assert_equal new_date, updated[0][0]
+  end
+
+  test "can create CSV with expected columns and field mappings with validators" do
+    date_field = Import::Field.new \
+      key: "date",
+      label: "Date",
+      validator: method(:validate_iso_date)
+
+    name_field = Import::Field.new \
+      key: "name",
+      label: "Name"
+
+    fields = [ date_field, name_field ]
+
+    raw_csv_str = <<-ROWS
+      date,Custom Field Header,extra_field
+      invalid_date_value,Starbucks drink,Food
+      2024-01-02,Amazon stuff,Shopping
+    ROWS
+
+    mappings = {
+      "name" => "Custom Field Header"
+    }
+
+    csv = Import::Csv.create_with_field_mappings(raw_csv_str, fields, mappings)
+
+    assert_equal %w[ date name ], csv.table.headers
+    assert_equal 2, csv.table.size
+    assert_equal "Amazon stuff", csv.table[1][1]
+  end
+
+  private
+
+    def validate_iso_date(value)
+      Date.iso8601(value)
+      true
+    rescue
+      false
+    end
+end

test/models/import/field_test.rb

@@ -0,0 +1,28 @@
+require "test_helper"
+
+class Import::FieldTest < ActiveSupport::TestCase
+  test "key is always a string" do
+    field1 = Import::Field.new label: "Test", key: "test"
+    field2 = Import::Field.new label: "Test2", key: :test2
+
+    assert_equal "test", field1.key
+    assert_equal "test2", field2.key
+  end
+
+  test "can set and override a validator for a field" do
+    field = Import::Field.new \
+      label: "Test",
+      key: "Test",
+      validator: ->(val) { val == 42 }
+
+    assert field.validate(42)
+    assert_not field.validate(41)
+
+    field.define_validator do |value|
+      value == 100
+    end
+
+    assert field.validate(100)
+    assert_not field.validate(42)
+  end
+end

test/models/import_test.rb

@@ -0,0 +1,61 @@
+require "test_helper"
+
+class ImportTest < ActiveSupport::TestCase
+  include ImportTestHelper, ActiveJob::TestHelper
+
+  setup do
+    @empty_import = imports(:empty_import)
+    @loaded_import = imports(:loaded_import)
+  end
+
+  test "raw csv input must conform to csv spec" do
+    @empty_import.raw_csv_str = malformed_csv_str
+    assert_not @empty_import.valid?
+
+    @empty_import.raw_csv_str = valid_csv_str
+    assert @empty_import.valid?
+  end
+
+  test "can update csv value without affecting raw input" do
+    assert_equal "Starbucks drink", @loaded_import.csv.table[0][1]
+
+    prior_raw_csv_str_value = @loaded_import.raw_csv_str
+    prior_normalized_csv_str_value = @loaded_import.normalized_csv_str
+
+    @loaded_import.update_csv! \
+      row_idx: 0,
+      col_idx: 1,
+      value: "new_category"
+
+    assert_equal "new_category", @loaded_import.csv.table[0][1]
+    assert_equal prior_raw_csv_str_value, @loaded_import.raw_csv_str
+    assert_not_equal prior_normalized_csv_str_value, @loaded_import.normalized_csv_str
+  end
+
+  test "publishes later" do
+    assert_enqueued_with(job: ImportJob) do
+      @loaded_import.publish_later
+    end
+  end
+
+  test "publishes a valid import" do
+    assert_difference "Transaction.count", 2 do
+      @loaded_import.publish
+    end
+
+    @loaded_import.reload
+
+    assert @loaded_import.complete?
+  end
+
+  test "failed publish results in error status" do
+    @empty_import.update! raw_csv_str: valid_csv_with_invalid_values
+
+    assert_difference "Transaction.count", 0 do
+      @empty_import.publish
+    end
+
+    @empty_import.reload
+    assert @empty_import.failed?
+  end
+end