diff --git a/.devcontainer/Dockerfile b/.devcontainer/Dockerfile
new file mode 100644
index 0000000..5575ad5
--- /dev/null
+++ b/.devcontainer/Dockerfile
@@ -0,0 +1,13 @@
+FROM python:3.10-slim
+
+WORKDIR /app
+
+# Install git and other potential dependencies
+RUN apt-get update && apt-get install -y git && rm -rf /var/lib/apt/lists/*
+
+COPY requirements.txt requirements-dev.txt ./
+RUN pip install --no-cache-dir -r requirements.txt -r requirements-dev.txt
+
+COPY . .
+
+CMD ["pytest"]
diff --git a/.devcontainer/devcontainer.json b/.devcontainer/devcontainer.json
new file mode 100644
index 0000000..bd2e116
--- /dev/null
+++ b/.devcontainer/devcontainer.json
@@ -0,0 +1,14 @@
+{
+	"name": "ItsPrompt Dev",
+	"build": {
+		"dockerfile": "Dockerfile"
+	},
+    "customizations": {
+        "vscode": {
+            "extensions": [
+                "ms-python.python",
+                "ms-python.vscode-pylance"
+            ]
+        }
+    }
+}
diff --git a/tests/data/test_expand.py b/tests/data/test_expand.py
index 09a3da6..e453300 100644
--- a/tests/data/test_expand.py
+++ b/tests/data/test_expand.py
@@ -86,3 +86,10 @@ def test_process_data_with_separator():
     ans = process_data(options)
 
     assert ans.with_separators == result
+
+
+def test_expand_options_get_option_returns_none():
+    options = ("first", "second")
+    ans = process_data(options)
+
+    assert ans.get_option("z") is None
diff --git a/tests/prompts/test_checkbox_prompt.py b/tests/prompts/test_checkbox_prompt.py
index fd85a8e..74a0565 100644
--- a/tests/prompts/test_checkbox_prompt.py
+++ b/tests/prompts/test_checkbox_prompt.py
@@ -96,4 +96,14 @@ def test_checkbox_raises_invalid_disabled():
         ans = Prompt.checkbox("", options, disabled=("invalid",))
 
 
+def test_checkbox_min_selections(send_keys):
+    options = ("first", "second")
+    # Try to enter without selection (blocked), then select "first", then enter (success)
+    send_keys(Keys.Enter, " ", Keys.Enter)
+
+    ans = Prompt.checkbox("", options, min_selections=1)
+
+    assert ans == ["first"]
+
+
 # TODO check min selections with error box (visual)
diff --git a/tests/prompts/test_input_prompt.py b/tests/prompts/test_input_prompt.py
index 4a9ff83..9567d2a 100644
--- a/tests/prompts/test_input_prompt.py
+++ b/tests/prompts/test_input_prompt.py
@@ -76,6 +76,16 @@ def test_input_raises_keyboard_interrupt(send_keys):
         ans = Prompt.input("")
 
 
+def test_input_validation(send_keys):
+    # validator requires at least 2 characters
+    # send "v", Enter (blocked), "a", Enter (success)
+    send_keys("v", Keys.Enter, "a", Keys.Enter)
+
+    ans = Prompt.input("", validate=lambda x: len(x) > 1)
+
+    assert ans == "va"
+
+
 # TODO input show_symbol is showing symbol (visual)
 # TODO input completer/completions is working (visual, functional)
 # TODO input validation is showing error (visual)