diff --git a/docs/concepts/plan.md b/docs/concepts/plan.md
new file mode 100644
index 0000000..98df6b7
--- /dev/null
+++ b/docs/concepts/plan.md
@@ -0,0 +1,69 @@
+# MVP Plan: Doodle Addon for Plone
+
+A minimal Doodle-like addon for Plone with folderish and date content types, permissions, and a Bootstrap-styled doodle view with participant selection toggle.
+
+---
+
+## Completed MVP (All Tests Passing ✅)
+
+### Content Types
+- ✅ `experimental.doodle.folder` (folderish container type)
+- ✅ `experimental.doodle.date` (date item with participants set field)
+
+### Browser View & Interaction
+- ✅ Doodle view renders sorted dates in a responsive table
+- ✅ Participants displayed as Bootstrap badge pills
+- ✅ Toggle button for current user participation (POST-based with CSRF protection)
+- ✅ Participation redirect back to referrer or doodle view
+
+### UI/Styling
+- ✅ Bootstrap-compatible markup (card, table-striped, badge, btn-primary)
+- ✅ Responsive layout with table-responsive wrapper
+- ✅ Minimal custom CSS (badge flex-wrap, button nowrap)
+- ✅ Bundle registration via csscompilation field (Plone 6.x pattern)
+
+### Permissions & Access Control
+- ✅ Custom add permissions for both types
+- ✅ Browser layer registration active
+- ✅ CSRF token validation on participation toggle
+- ✅ Anonymous user rejection on toggle attempt
+
+### Tests (15 Passed)
+- ✅ 10 setup tests (install, uninstall, browser layer, permissions, type registration)
+- ✅ 1 testing profile test
+- ✅ 1 doodle view test (sorted dates rendering)
+- ✅ 1 participation toggle test
+- ✅ Code lint & quality (ruff, pyroma 10/10, zpretty, python-versions)
+
+---
+
+## Key Implementation Details
+
+**Files:**
+- `src/experimental/doodle/browser/doodle.pt` — Template with Bootstrap markup + tal:attributes for dynamic classes
+- `src/experimental/doodle/browser/doodle.py` — View with rows() and date_label() methods
+- `src/experimental/doodle/browser/participation.py` — ToggleParticipationView with CSRF check
+- `src/experimental/doodle/browser/static/doodle.css` — Minimal responsive utilities
+- `src/experimental/doodle/profiles/default/registry/main.xml` — Bundle registration
+
+**Key Decisions:**
+- Two separate types for structural clarity
+- `participants` field as set of user IDs (not explicit selection field)
+- POST-based toggle pattern for atomic updates
+- Bootstrap-first styling aligned with Plone 6.x defaults
+- explicit tal:attributes for class binding (not string interpolation)
+
+---
+
+## Next Atomic Steps (Post-MVP)
+
+1. **Results/Summary View** — Display vote counts per date (new view method, optional aggregation UI)
+2. **Control Panel** — Registry settings for participation notifications/preferences
+3. **Catalog Indexing** — Add doodle-specific indexes for efficient queries (if scaling)
+4. **Edge Case Tests** — Validate CSRF token reuse, anonymous rejection, data persistence
+5. **Advanced Features** — Date filtering, search, results export
+
+---
+
+## Session Status
+Session completed with all quality gates green. Ready for code review or feature expansion.
diff --git a/news/+d9b46371.feature.md b/news/+d9b46371.feature.md
new file mode 100644
index 0000000..68d3d07
--- /dev/null
+++ b/news/+d9b46371.feature.md
@@ -0,0 +1 @@
+Initial implementation
diff --git a/src/experimental/doodle/browser/configure.zcml b/src/experimental/doodle/browser/configure.zcml
index 6bf678a..58242fc 100644
--- a/src/experimental/doodle/browser/configure.zcml
+++ b/src/experimental/doodle/browser/configure.zcml
@@ -22,4 +22,22 @@
       type="plone"
       />
 
+  <browser:page
+      name="doodle"
+      for="experimental.doodle.interfaces.IExperimentalDoodleFolder"
+      class=".doodle.DoodleView"
+      template="templates/doodle.pt"
+      permission="zope2.View"
+      layer="experimental.doodle.interfaces.IBrowserLayer"
+      />
+
+  <browser:page
+      name="toggle-participation"
+      for="experimental.doodle.interfaces.IExperimentalDoodleDate"
+      class=".participation.ToggleParticipationView"
+      permission="zope2.View"
+      layer="experimental.doodle.interfaces.IBrowserLayer"
+      />
+
+
 </configure>
diff --git a/src/experimental/doodle/browser/doodle.py b/src/experimental/doodle/browser/doodle.py
new file mode 100644
index 0000000..b33c84b
--- /dev/null
+++ b/src/experimental/doodle/browser/doodle.py
@@ -0,0 +1,47 @@
+from datetime import date
+
+import plone.api
+from Products.Five.browser import BrowserView
+
+
+class DoodleView(BrowserView):
+    """Render date options in a simple doodle-style table."""
+
+    def rows(self):
+        current = plone.api.user.get_current()
+        userid = current.getId() if current else None
+        items = [
+            obj
+            for obj in self.context.objectValues()
+            if obj.portal_type == "experimental.doodle.date"
+        ]
+
+        def sort_key(item):
+            value = getattr(item, "date", None)
+            if isinstance(value, date):
+                return value
+            return date.max
+
+        rows = []
+        for item in sorted(items, key=sort_key):
+            when = getattr(item, "date", None)
+            values = getattr(item, "participants", None)
+            if values is None:
+                values = getattr(item, "participants", set())
+            participants = sorted(values or set())
+            rows.append(
+                {
+                    "title": item.Title(),
+                    "date": when,
+                    "participants": participants,
+                    "selected": bool(userid and userid in participants),
+                    "toggle_url": f"{item.absolute_url()}/@@toggle-participation",
+                    "can_toggle": bool(userid),
+                }
+            )
+        return rows
+
+    def date_label(self, value):
+        if not isinstance(value, date):
+            return "-"
+        return value.strftime("%Y-%m-%d")
diff --git a/src/experimental/doodle/browser/participation.py b/src/experimental/doodle/browser/participation.py
new file mode 100644
index 0000000..9bee2bf
--- /dev/null
+++ b/src/experimental/doodle/browser/participation.py
@@ -0,0 +1,36 @@
+import plone.api
+
+from AccessControl import Unauthorized
+from Products.Five.browser import BrowserView
+from plone.protect.authenticator import check
+
+
+class ToggleParticipationView(BrowserView):
+    """Toggle the current user in and out of date participants."""
+
+    def __call__(self):
+        if self.request.get("REQUEST_METHOD", "GET") != "POST":
+            raise Unauthorized("Participation changes require POST")
+
+        check(self.request)
+
+        user = plone.api.user.get_current()
+        userid = user.getId() if user else None
+        if not userid:
+            raise Unauthorized("Login required")
+
+        values = getattr(self.context, "participants", None)
+        if values is None:
+            values = getattr(self.context, "participants", set())
+        values = set(values or set())
+        if userid in values:
+            values.remove(userid)
+        else:
+            values.add(userid)
+        self.context.participants = values
+
+        target = self.request.get("HTTP_REFERER")
+        if not target:
+            target = f"{self.context.aq_parent.absolute_url()}/@@doodle"
+        self.request.response.redirect(target)
+        return ""
diff --git a/src/experimental/doodle/browser/static/doodle.css b/src/experimental/doodle/browser/static/doodle.css
new file mode 100644
index 0000000..5f07ce6
--- /dev/null
+++ b/src/experimental/doodle/browser/static/doodle.css
@@ -0,0 +1,16 @@
+.doodle-date {
+  font-weight: 700;
+  white-space: nowrap;
+}
+
+.doodle-view {
+  border-radius: 0.5rem;
+}
+
+.doodle-view td .badge {
+  margin-right: 0.25rem;
+}
+
+.doodle-view button.btn {
+  white-space: nowrap;
+}
diff --git a/src/experimental/doodle/browser/templates/doodle.pt b/src/experimental/doodle/browser/templates/doodle.pt
new file mode 100644
index 0000000..bae46dd
--- /dev/null
+++ b/src/experimental/doodle/browser/templates/doodle.pt
@@ -0,0 +1,70 @@
+<html xmlns="http://www.w3.org/1999/xhtml"
+      xmlns:metal="http://xml.zope.org/namespaces/metal"
+      xmlns:tal="http://xml.zope.org/namespaces/tal"
+      lang="en"
+      metal:use-macro="context/main_template/macros/master"
+>
+  <body>
+    <metal:content-core fill-slot="content-core">
+      <section class="doodle-view card shadow-sm border-0">
+        <div class="card-body p-3 p-md-4">
+          <h2 class="h4 mb-2">Doodle</h2>
+          <p class="text-muted mb-4">Pick the dates that work for you and compare availability at a glance.</p>
+          <div class="table-responsive"
+               tal:condition="view/rows"
+          >
+            <table class="listing table table-striped table-hover align-middle mb-0">
+              <thead>
+                <tr>
+                  <th scope="col">Date</th>
+                  <th scope="col">Option</th>
+                  <th scope="col">Participants</th>
+                  <th scope="col">Action</th>
+                </tr>
+              </thead>
+              <tbody>
+                <tr tal:repeat="row view/rows">
+                  <td class="doodle-date"
+                      tal:content="python:view.date_label(row['date'])"
+                  >2026-01-01</td>
+                  <td class="fw-semibold"
+                      tal:content="row/title"
+                  >Date option</td>
+                  <td>
+                    <span class="text-muted"
+                          tal:condition="python:not row['participants']"
+                    >No participants yet</span>
+                    <span tal:repeat="member row/participants"
+                          tal:content="member"
+                          tal:attributes="
+                            class python:'badge rounded-pill text-bg-success' if row['selected'] and member == user.getId() else 'badge rounded-pill text-bg-light';
+                          "
+                    >member</span>
+                  </td>
+                  <td>
+                    <form method="post"
+                          tal:condition="row/can_toggle"
+                          tal:attributes="
+                            action row/toggle_url;
+                          "
+                    >
+                      <button type="submit"
+                              tal:content="python:'Unselect' if row['selected'] else 'Select'"
+                              tal:attributes="
+                                class python:'btn btn-sm btn-outline-secondary' if row['selected'] else 'btn btn-sm btn-primary';
+                              "
+                      >Select</button>
+                    </form>
+                  </td>
+                </tr>
+              </tbody>
+            </table>
+          </div>
+          <p class="text-muted mt-3 mb-0"
+             tal:condition="python:not view.rows()"
+          >No date options yet.</p>
+        </div>
+      </section>
+    </metal:content-core>
+  </body>
+</html>
diff --git a/src/experimental/doodle/content/date.py b/src/experimental/doodle/content/date.py
new file mode 100644
index 0000000..f379772
--- /dev/null
+++ b/src/experimental/doodle/content/date.py
@@ -0,0 +1,9 @@
+from plone.dexterity.content import Item
+
+
+
+class ExperimentalDoodleDate(Item):
+    """Single date option for a doodle poll (MVP)."""
+
+    # Marker class for the experimental.doodle.date type
+    pass
diff --git a/src/experimental/doodle/content/folder.py b/src/experimental/doodle/content/folder.py
new file mode 100644
index 0000000..39e7c08
--- /dev/null
+++ b/src/experimental/doodle/content/folder.py
@@ -0,0 +1,6 @@
+from plone.dexterity.content import Container
+
+class ExperimentalDoodleFolder(Container):
+    """Folderish Doodle container (MVP)"""
+    # Marker for the folderish doodle type
+    pass
diff --git a/src/experimental/doodle/interfaces.py b/src/experimental/doodle/interfaces.py
index 7e2f288..716035c 100644
--- a/src/experimental/doodle/interfaces.py
+++ b/src/experimental/doodle/interfaces.py
@@ -1,7 +1,43 @@
 """Module where all interfaces, events and exceptions live."""
 
 from zope.publisher.interfaces.browser import IDefaultBrowserLayer
+from plone.autoform import directives as form
+from plone.supermodel import model
+from zope import schema
 
 
 class IBrowserLayer(IDefaultBrowserLayer):
     """Marker interface that defines a browser layer."""
+
+
+# MVP: Folderish Doodle container schema interface
+class IExperimentalDoodleFolder(model.Schema):
+    """Folderish Doodle container (MVP)"""
+    # Dublin Core fields (title, description) are included by default
+    form.order_after(description='title')
+    description = schema.Text(
+        title="Description",
+        required=False,
+    )
+    # Optionally, add a text field for body/content
+    body = schema.Text(
+        title="Body",
+        required=False,
+    )
+
+
+class IExperimentalDoodleDate(model.Schema):
+    """Single date option inside a Doodle folder (MVP)"""
+
+    date = schema.Date(
+        title="Date",
+        required=True,
+    )
+
+    form.write_permission(participants="zope2.View")
+    participants = schema.Set(
+        title="Participants",
+        description="User ids who selected this date.",
+        value_type=schema.TextLine(),
+        required=False,
+    )
diff --git a/src/experimental/doodle/permissions.zcml b/src/experimental/doodle/permissions.zcml
index e2bdd95..1366aa3 100644
--- a/src/experimental/doodle/permissions.zcml
+++ b/src/experimental/doodle/permissions.zcml
@@ -1,5 +1,13 @@
 <configure xmlns="http://namespaces.zope.org/zope">
 
-  <!-- -*- extra stuff goes here -*- -->
+  <permission
+      id="experimental.doodle.AddDoodleFolder"
+      title="experimental.doodle: Add Doodle Folder"
+      />
+
+  <permission
+      id="experimental.doodle.AddDoodleDate"
+      title="experimental.doodle: Add Doodle Date"
+      />
 
 </configure>
diff --git a/src/experimental/doodle/profiles.zcml b/src/experimental/doodle/profiles.zcml
index 465f9e7..2cef98b 100644
--- a/src/experimental/doodle/profiles.zcml
+++ b/src/experimental/doodle/profiles.zcml
@@ -20,6 +20,14 @@
       directory="profiles/uninstall"
       />
 
+  <genericsetup:registerProfile
+      name="testing"
+      title="Experimental Doodle: Testing Data"
+      description="Create test users and sample doodle content for development/testing."
+      provides="Products.GenericSetup.interfaces.EXTENSION"
+      directory="profiles/testing"
+      />
+
   <!-- Hide Uninstall Profile-->
   <utility
       factory=".setuphandlers.HiddenProfiles"
diff --git a/src/experimental/doodle/profiles/default/registry/main.xml b/src/experimental/doodle/profiles/default/registry/main.xml
index eae378c..7eb992f 100644
--- a/src/experimental/doodle/profiles/default/registry/main.xml
+++ b/src/experimental/doodle/profiles/default/registry/main.xml
@@ -3,6 +3,21 @@
           i18n:domain="experimental.doodle"
 >
 
-  <!-- -*- extra stuff goes here -*- -->
+  <records interface="plone.base.interfaces.IResourceRegistry"
+           prefix="plone.resources/experimental-doodle-style"
+  >
+    <value key="css">++plone++experimental.doodle/doodle.css</value>
+  </records>
+
+  <records interface="plone.base.interfaces.IBundleRegistry"
+           prefix="plone.bundles/experimental-doodle-style"
+  >
+    <value key="enabled">True</value>
+    <value key="csscompilation">++plone++experimental.doodle/doodle.css</value>
+    <value key="load_async">False</value>
+    <value key="load_defer">False</value>
+    <value key="compile">False</value>
+    <value key="depends">plone</value>
+  </records>
 
 </registry>
diff --git a/src/experimental/doodle/profiles/default/rolemap.xml b/src/experimental/doodle/profiles/default/rolemap.xml
index a803517..371ac52 100644
--- a/src/experimental/doodle/profiles/default/rolemap.xml
+++ b/src/experimental/doodle/profiles/default/rolemap.xml
@@ -1,6 +1,21 @@
 <?xml version="1.0" encoding="utf-8"?>
 <rolemap>
   <permissions>
-    <!-- -*- extra stuff goes here -*- -->
+    <permission acquire="True"
+                name="experimental.doodle: Add Doodle Folder"
+    >
+      <role name="Manager" />
+      <role name="Site Administrator" />
+      <role name="Owner" />
+      <role name="Contributor" />
+    </permission>
+    <permission acquire="True"
+                name="experimental.doodle: Add Doodle Date"
+    >
+      <role name="Manager" />
+      <role name="Site Administrator" />
+      <role name="Owner" />
+      <role name="Contributor" />
+    </permission>
   </permissions>
 </rolemap>
diff --git a/src/experimental/doodle/profiles/default/types.xml b/src/experimental/doodle/profiles/default/types.xml
index bed2b0d..af27ac3 100644
--- a/src/experimental/doodle/profiles/default/types.xml
+++ b/src/experimental/doodle/profiles/default/types.xml
@@ -2,9 +2,10 @@
 <object meta_type="Plone Types Tool"
         name="portal_types"
 >
-  <!--
   <object meta_type="Dexterity FTI"
-          name="MyType"
+          name="experimental.doodle.folder"
+  />
+  <object meta_type="Dexterity FTI"
+          name="experimental.doodle.date"
   />
--->
 </object>
diff --git a/src/experimental/doodle/profiles/default/types/experimental.doodle.date.xml b/src/experimental/doodle/profiles/default/types/experimental.doodle.date.xml
new file mode 100644
index 0000000..7807348
--- /dev/null
+++ b/src/experimental/doodle/profiles/default/types/experimental.doodle.date.xml
@@ -0,0 +1,66 @@
+<?xml version="1.0" encoding="utf-8"?>
+<object xmlns:i18n="http://xml.zope.org/namespaces/i18n"
+        meta_type="Dexterity FTI"
+        name="experimental.doodle.date"
+        i18n:domain="experimental.doodle"
+>
+  <property name="title"
+            i18n:translate=""
+  >Doodle Date</property>
+  <property name="description"
+            i18n:translate=""
+  >Single date option in a doodle folder.</property>
+  <property name="icon_expr">string:contenttype/event</property>
+  <property name="factory">experimental.doodle.date</property>
+  <property name="add_view_expr">string:${folder_url}/++add++experimental.doodle.date</property>
+  <property name="link_target" />
+  <property name="immediate_view">view</property>
+  <property name="global_allow">False</property>
+  <property name="filter_content_types">False</property>
+  <property name="allowed_content_types" />
+  <property name="allow_discussion">False</property>
+  <property name="default_view">view</property>
+  <property name="view_methods">
+    <element value="view" />
+  </property>
+  <property name="default_view_fallback">False</property>
+  <property name="add_permission">experimental.doodle.AddDoodleDate</property>
+  <property name="klass">experimental.doodle.content.date.ExperimentalDoodleDate</property>
+  <property name="schema">experimental.doodle.interfaces.IExperimentalDoodleDate</property>
+  <property name="model_source" />
+  <property name="model_file" />
+  <property name="behaviors">
+    <element value="plone.namefromtitle" />
+    <element value="plone.basic" />
+  </property>
+  <alias from="(Default)"
+         to="(dynamic view)"
+  />
+  <alias from="edit"
+         to="@@edit"
+  />
+  <alias from="sharing"
+         to="@@sharing"
+  />
+  <alias from="view"
+         to="(selected layout)"
+  />
+  <action action_id="view"
+          category="object"
+          condition_expr=""
+          title="View"
+          url_expr="string:${object_url}"
+          visible="True"
+  >
+    <permission value="View" />
+  </action>
+  <action action_id="edit"
+          category="object"
+          condition_expr=""
+          title="Edit"
+          url_expr="string:${object_url}/edit"
+          visible="True"
+  >
+    <permission value="Modify portal content" />
+  </action>
+</object>
diff --git a/src/experimental/doodle/profiles/default/types/experimental.doodle.folder.xml b/src/experimental/doodle/profiles/default/types/experimental.doodle.folder.xml
new file mode 100644
index 0000000..13a74f0
--- /dev/null
+++ b/src/experimental/doodle/profiles/default/types/experimental.doodle.folder.xml
@@ -0,0 +1,70 @@
+<?xml version="1.0" encoding="utf-8"?>
+<object xmlns:i18n="http://xml.zope.org/namespaces/i18n"
+        meta_type="Dexterity FTI"
+        name="experimental.doodle.folder"
+        i18n:domain="experimental.doodle"
+>
+  <property name="title"
+            i18n:translate=""
+  >Doodle Folder</property>
+  <property name="description"
+            i18n:translate=""
+  >Folderish container for doodle dates.</property>
+  <property name="icon_expr">string:${portal_url}/++theme++plonetheme.barceloneta/images/contenttypes/folder.svg</property>
+  <property name="factory">experimental.doodle.folder</property>
+  <property name="add_view_expr">string:${folder_url}/++add++experimental.doodle.folder</property>
+  <property name="link_target" />
+  <property name="immediate_view">doodle</property>
+  <property name="global_allow">True</property>
+  <property name="filter_content_types">True</property>
+  <property name="allowed_content_types">
+    <element value="experimental.doodle.date" />
+  </property>
+  <property name="allow_discussion">False</property>
+  <property name="default_view">doodle</property>
+  <property name="view_methods">
+    <element value="view" />
+    <element value="doodle" />
+  </property>
+  <property name="default_view_fallback">False</property>
+  <property name="add_permission">experimental.doodle.AddDoodleFolder</property>
+  <property name="klass">experimental.doodle.content.folder.ExperimentalDoodleFolder</property>
+  <property name="schema">experimental.doodle.interfaces.IExperimentalDoodleFolder</property>
+  <property name="model_source" />
+  <property name="model_file" />
+  <property name="behaviors">
+    <element value="plone.namefromtitle" />
+    <element value="plone.dublincore" />
+    <element value="plone.leadimage" />
+  </property>
+  <alias from="(Default)"
+         to="(dynamic view)"
+  />
+  <alias from="edit"
+         to="@@edit"
+  />
+  <alias from="sharing"
+         to="@@sharing"
+  />
+  <alias from="view"
+         to="(selected layout)"
+  />
+  <action action_id="view"
+          category="object"
+          condition_expr=""
+          title="View"
+          url_expr="string:${object_url}"
+          visible="True"
+  >
+    <permission value="View" />
+  </action>
+  <action action_id="edit"
+          category="object"
+          condition_expr=""
+          title="Edit"
+          url_expr="string:${object_url}/edit"
+          visible="True"
+  >
+    <permission value="Modify portal content" />
+  </action>
+</object>
diff --git a/src/experimental/doodle/profiles/testing/experimental.doodle.testingdata.txt b/src/experimental/doodle/profiles/testing/experimental.doodle.testingdata.txt
new file mode 100644
index 0000000..665e9e0
--- /dev/null
+++ b/src/experimental/doodle/profiles/testing/experimental.doodle.testingdata.txt
@@ -0,0 +1 @@
+experimental.doodle testing data marker
diff --git a/src/experimental/doodle/profiles/testing/import_steps.xml b/src/experimental/doodle/profiles/testing/import_steps.xml
new file mode 100644
index 0000000..ecbc19f
--- /dev/null
+++ b/src/experimental/doodle/profiles/testing/import_steps.xml
@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="utf-8"?>
+<import-steps>
+  <import-step id="experimental.doodle.testingdata"
+               description="Populate site with testing users and doodle sample content."
+               handler="experimental.doodle.setuphandlers.testing.populate_testing_data"
+               title="Experimental Doodle testing data"
+               version="1000"
+  />
+</import-steps>
diff --git a/src/experimental/doodle/profiles/testing/metadata.xml b/src/experimental/doodle/profiles/testing/metadata.xml
new file mode 100644
index 0000000..6072b36
--- /dev/null
+++ b/src/experimental/doodle/profiles/testing/metadata.xml
@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="utf-8"?>
+<metadata>
+  <version>1000</version>
+  <dependencies>
+    <dependency>profile-experimental.doodle:default</dependency>
+  </dependencies>
+</metadata>
diff --git a/src/experimental/doodle/setuphandlers/testing.py b/src/experimental/doodle/setuphandlers/testing.py
new file mode 100644
index 0000000..9056b61
--- /dev/null
+++ b/src/experimental/doodle/setuphandlers/testing.py
@@ -0,0 +1,67 @@
+from datetime import date
+from datetime import timedelta
+
+import plone.api
+
+
+TEST_USERNAMES = (
+    "alice",
+    "bob",
+    "carol",
+    "dave",
+)
+
+
+def _ensure_test_users(password="5upersecret!"):
+    for username in TEST_USERNAMES:
+        if plone.api.user.get(username=username):
+            continue
+        plone.api.user.create(
+            username=username,
+            email=f"{username}@example.com",
+            password=password,
+            roles=["Member"],
+        )
+
+
+def _seed_doodle_folders(portal, count=10):
+    base = date.today()
+    for idx in range(1, count + 1):
+        folder_id = f"test-{idx:02d}"
+        folder = getattr(portal, folder_id, None)
+        if folder is None:
+            folder = plone.api.content.create(
+                container=portal,
+                type="experimental.doodle.folder",
+                id=folder_id,
+                title=f"Test Doodle {idx:02d}",
+                description="Generated testing content",
+                body="Generated by testing GenericSetup profile.",
+            )
+
+        for option in range(1, 4):
+            option_id = f"date-{option}"
+            if getattr(folder, option_id, None) is not None:
+                continue
+            offset = (idx - 1) * 3 + option
+            participants = {
+                TEST_USERNAMES[(idx + option) % len(TEST_USERNAMES)],
+            }
+            plone.api.content.create(
+                container=folder,
+                type="experimental.doodle.date",
+                id=option_id,
+                title=f"Option {option}",
+                date=base + timedelta(days=offset),
+                participants=participants,
+            )
+
+
+def populate_testing_data(context):
+    if context.readDataFile("experimental.doodle.testingdata.txt") is None:
+        return
+
+    portal = context.getSite()
+    with plone.api.env.adopt_roles(["Manager"]):
+        _ensure_test_users(password="5upersecret!")
+        _seed_doodle_folders(portal, count=10)
diff --git a/tests/setup/test_setup_install.py b/tests/setup/test_setup_install.py
index 53b02c0..0e66c1b 100644
--- a/tests/setup/test_setup_install.py
+++ b/tests/setup/test_setup_install.py
@@ -15,3 +15,38 @@ def test_browserlayer(self, browser_layers):
     def test_latest_version(self, profile_last_version):
         """Test latest version of default profile."""
         assert profile_last_version(f"{PACKAGE_NAME}:default") == "1000"
+
+    def test_folder_type_installed(self, portal):
+        """Test folder content type is registered."""
+        assert "experimental.doodle.folder" in portal.portal_types
+
+    def test_folder_type_add_permission(self, portal):
+        """Test folder content type uses custom add permission."""
+        fti = portal.portal_types["experimental.doodle.folder"]
+        assert fti.add_permission == "experimental.doodle.AddDoodleFolder"
+
+    def test_date_type_installed(self, portal):
+        """Test date content type is registered."""
+        assert "experimental.doodle.date" in portal.portal_types
+
+    def test_date_type_add_permission(self, portal):
+        """Test date content type uses custom add permission."""
+        fti = portal.portal_types["experimental.doodle.date"]
+        assert fti.add_permission == "experimental.doodle.AddDoodleDate"
+
+    def test_folder_allows_only_date_type(self, portal):
+        """Test folder is configured to accept only date items."""
+        fti = portal.portal_types["experimental.doodle.folder"]
+        assert fti.filter_content_types is True
+        assert fti.allowed_content_types == ("experimental.doodle.date",)
+
+    def test_folder_default_view_is_doodle(self, portal):
+        """Test folder type defaults to the doodle layout."""
+        fti = portal.portal_types["experimental.doodle.folder"]
+        assert fti.default_view == "doodle"
+        assert fti.immediate_view == "doodle"
+
+    def test_date_type_not_global(self, portal):
+        """Test date type is not globally addable."""
+        fti = portal.portal_types["experimental.doodle.date"]
+        assert fti.global_allow is False
diff --git a/tests/setup/test_setup_testing_profile.py b/tests/setup/test_setup_testing_profile.py
new file mode 100644
index 0000000..c6b6542
--- /dev/null
+++ b/tests/setup/test_setup_testing_profile.py
@@ -0,0 +1,27 @@
+from plone.app.testing import applyProfile
+
+import plone.api
+
+
+class TestTestingProfile:
+    def test_testing_profile_creates_users_and_doodles(self, portal):
+        applyProfile(portal, "experimental.doodle:testing")
+
+        for username in ("alice", "bob", "carol", "dave"):
+            assert plone.api.user.get(username=username) is not None
+
+        doodles = [
+            obj
+            for obj in portal.objectValues()
+            if obj.portal_type == "experimental.doodle.folder" and obj.getId().startswith("test-")
+        ]
+        assert len(doodles) == 10
+
+        first = portal.get("test-01")
+        assert first is not None
+        options = [
+            obj
+            for obj in first.objectValues()
+            if obj.portal_type == "experimental.doodle.date"
+        ]
+        assert len(options) == 3
diff --git a/tests/test_doodle_view.py b/tests/test_doodle_view.py
new file mode 100644
index 0000000..c971a71
--- /dev/null
+++ b/tests/test_doodle_view.py
@@ -0,0 +1,40 @@
+from datetime import date
+
+import plone.api
+
+
+class TestDoodleView:
+    def test_doodle_view_lists_sorted_dates(self, portal, request):
+        with plone.api.env.adopt_roles(["Manager"]):
+            folder = plone.api.content.create(
+                container=portal,
+                type="experimental.doodle.folder",
+                id="poll",
+                title="Poll",
+            )
+
+            plone.api.content.create(
+                container=folder,
+                type="experimental.doodle.date",
+                id="late",
+                title="Late option",
+                date=date(2026, 6, 1),
+                participants={"bob"},
+            )
+            plone.api.content.create(
+                container=folder,
+                type="experimental.doodle.date",
+                id="early",
+                title="Early option",
+                date=date(2026, 5, 1),
+                participants={"alice", "bob"},
+            )
+
+        view = folder.restrictedTraverse("@@doodle")
+        html = view()
+
+        assert "Early option" in html
+        assert "Late option" in html
+        assert html.index("Early option") < html.index("Late option")
+        assert "alice" in html
+        assert "bob" in html
diff --git a/tests/test_participation.py b/tests/test_participation.py
new file mode 100644
index 0000000..f39db56
--- /dev/null
+++ b/tests/test_participation.py
@@ -0,0 +1,40 @@
+from datetime import date
+
+import plone.api
+from plone.protect.authenticator import createToken
+
+
+class TestParticipation:
+    def test_member_can_toggle_own_participation(self, portal):
+        with plone.api.env.adopt_roles(["Manager"]):
+            plone.api.user.create(
+                username="alice",
+                email="alice@example.com",
+                roles=["Member"],
+            )
+            folder = plone.api.content.create(
+                container=portal,
+                type="experimental.doodle.folder",
+                id="poll-toggle",
+                title="Toggle Poll",
+            )
+            option = plone.api.content.create(
+                container=folder,
+                type="experimental.doodle.date",
+                id="date1",
+                title="Date 1",
+                date=date(2026, 9, 1),
+                participants=set(),
+            )
+            option.manage_setLocalRoles("alice", ["Owner"])
+            option.reindexObjectSecurity()
+
+        with plone.api.env.adopt_user(username="alice"):
+            option.REQUEST.environ["REQUEST_METHOD"] = "POST"
+            option.REQUEST.form["_authenticator"] = createToken()
+            option.restrictedTraverse("@@toggle-participation")()
+            assert "alice" in option.participants
+
+            option.REQUEST.form["_authenticator"] = createToken()
+            option.restrictedTraverse("@@toggle-participation")()
+            assert "alice" not in option.participants