Added popover trigger button scope

Encapsulates popover trigger functionality which includes the ability to uniquely configure `interestfor` (via `tip`) and `popovertarget` (via `target`) attributes. If these attributes are not supplied, they'll be removed from the DOM entirely.

Defaults to _info_ popover by default (currently, the most common).

Milestone: minor

app/templates/shared/popovers/triggers/_button.html.erb

@@ -0,0 +1,4 @@
+<%= tag.button type: :button, class: classes, interestfor: tip, popovertarget: target do %>
+  <%= image_tag icon_uri, class: :icon, width:, height:, loading: :lazy %>
+  <%= yield if block_given? %>
+<% end %>

app/views/scopes/popover_trigger_button.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+module Terminus
+  module Views
+    module Scopes
+      # A customizable popover trigger button.
+      class PopoverTriggerButton < Hanami::View::Scope
+        def classes = locals.fetch __method__, "bit-popover-trigger"
+
+        def height = locals.fetch __method__, 15
+
+        def icon = locals.fetch __method__, :info
+
+        def icon_uri = "icons/#{icon}.svg"
+
+        def render(path = "shared/popovers/triggers/button") = super
+
+        def target = locals[__method__].then { "popover-#{it}" if it }
+
+        def tip = locals[__method__].then { "tooltip-action-#{it}" if it }
+
+        def width = locals.fetch __method__, 15
+      end
+    end
+  end
+end

spec/app/views/scopes/popover_trigger_button_spec.rb

@@ -0,0 +1,110 @@
+# frozen_string_literal: true
+
+require "hanami_helper"
+
+RSpec.describe Terminus::Views::Scopes::PopoverTriggerButton do
+  subject(:scope) { described_class.new locals:, rendering: Terminus::View.new.rendering }
+
+  let(:locals) { {icon: :info} }
+
+  describe "#classes" do
+    it "answers default classes" do
+      expect(scope.classes).to eq("bit-popover-trigger")
+    end
+
+    it "answers custom classes" do
+      locals[:classes] = "one two three"
+      expect(scope.classes).to eq("one two three")
+    end
+  end
+
+  describe "#height" do
+    it "answers default height" do
+      expect(scope.height).to eq(15)
+    end
+
+    it "answers custom height" do
+      locals[:height] = 30
+      expect(scope.height).to eq(30)
+    end
+  end
+
+  describe "#icon" do
+    it "answers default icon" do
+      expect(scope.icon).to eq(:info)
+    end
+
+    it "answers custom icon" do
+      locals[:icon] = :test
+      expect(scope.icon).to eq(:test)
+    end
+  end
+
+  describe "#icon_uri" do
+    it "answers default URI" do
+      expect(scope.icon_uri).to eq("icons/info.svg")
+    end
+
+    it "answers custom URI" do
+      locals[:icon] = :test
+      expect(scope.icon_uri).to eq("icons/test.svg")
+    end
+  end
+
+  describe "#render" do
+    it "renders button" do
+      expect(scope.render).to include(%(<button type="button" class="bit-popover-trigger">))
+    end
+
+    it "renders image" do
+      expect(scope.render).to match(%r(assets/icons/info.*.svg))
+    end
+
+    it "renders with yielded content" do
+      content = scope.render { "A test." }
+      expect(content).to include("A test.")
+    end
+
+    it "renders with tip and target" do
+      locals.merge! tip: :test, target: :test
+
+      expect(scope.render).to include(
+        %(<button type="button" class="bit-popover-trigger" interestfor="tooltip-action-test" ) +
+        %(popovertarget="popover-test">)
+      )
+    end
+  end
+
+  describe "#target" do
+    it "answers nil when not set" do
+      expect(scope.target).to be(nil)
+    end
+
+    it "answers target when set" do
+      locals[:target] = :test
+      expect(scope.target).to eq("popover-test")
+    end
+  end
+
+  describe "#tip" do
+    it "answers nil when not set" do
+      expect(scope.tip).to be(nil)
+    end
+
+    it "answers tip when set" do
+      locals[:tip] = :test
+      expect(scope.tip).to eq("tooltip-action-test")
+    end
+  end
+
+  describe "#width" do
+    it "answers default height" do
+      expect(scope.width).to eq(15)
+    end
+
+    it "answers custom height" do
+      locals[:width] = 30
+      expect(scope.width).to eq(30)
+    end
+  end
+end