diff --git a/__test__/components/CalendarColors.test.tsx b/__test__/components/CalendarColors.test.tsx
new file mode 100644
index 0000000..8398e19
--- /dev/null
+++ b/__test__/components/CalendarColors.test.tsx
@@ -0,0 +1,378 @@
+import { fireEvent, screen, waitFor } from "@testing-library/react";
+import userEvent from "@testing-library/user-event";
+import { act } from "react";
+import CalendarSearch from "../../src/components/Calendar/CalendarSearch";
+import * as CalendarApi from "../../src/features/Calendars/CalendarApi";
+import * as CalendarSlice from "../../src/features/Calendars/CalendarSlice";
+import { searchUsers } from "../../src/features/User/userAPI";
+import { renderWithProviders } from "../utils/Renderwithproviders";
+
+jest.mock("../../src/features/User/userAPI");
+jest.mock("../../src/features/Calendars/CalendarApi");
+
+const mockedSearchUsers = searchUsers as jest.MockedFunction<
+  typeof searchUsers
+>;
+const mockedGetCalendars = CalendarApi.getCalendars as jest.MockedFunction<
+  typeof CalendarApi.getCalendars
+>;
+
+describe("CalendarSearch", () => {
+  const mockOnClose = jest.fn();
+  const mockUser = {
+    email: "user@example.com",
+    displayName: "Test User",
+    avatarUrl: "https://example.com/avatar.jpg",
+    openpaasId: "user123",
+  };
+
+  const mockCalendar = {
+    "dav:name": "Test Calendar",
+    "apple:color": "#FF0000",
+    _links: {
+      self: {
+        href: "/calendars/user123/cal1.json",
+      },
+    },
+  };
+
+  const preloadedState = {
+    user: {
+      userData: {
+        sub: "test",
+        email: "test@test.com",
+        sid: "mockSid",
+        openpaasId: "user1",
+      },
+      tokens: { accessToken: "token" },
+    },
+    calendars: {
+      list: {
+        "user1/cal1": {
+          name: "My Calendar",
+          id: "user1/cal1",
+          color: "#0000FF",
+          ownerEmails: ["test@test.com"],
+          events: {},
+        },
+      },
+      pending: false,
+    },
+  };
+
+  beforeEach(() => {
+    jest.clearAllMocks();
+  });
+
+  it("searches for users and displays their calendars", async () => {
+    mockedSearchUsers.mockResolvedValueOnce([mockUser]);
+    mockedGetCalendars.mockResolvedValueOnce({
+      _embedded: {
+        "dav:calendar": [mockCalendar],
+      },
+    });
+
+    await act(async () => {
+      renderWithProviders(
+        <CalendarSearch anchorEl={null} open={true} onClose={mockOnClose} />,
+        preloadedState
+      );
+    });
+
+    const input = screen.getByRole("combobox");
+    await act(async () => {
+      userEvent.type(input, "Test");
+    });
+
+    const option = await screen.findByText("Test User");
+    await act(async () => {
+      fireEvent.click(option);
+    });
+
+    await waitFor(() => {
+      expect(mockedGetCalendars).toHaveBeenCalledWith(
+        "user123",
+        "sharedPublic=true&withRights=true"
+      );
+    });
+
+    await waitFor(() => {
+      expect(screen.getByText("Test Calendar")).toBeInTheDocument();
+      expect(screen.getByText("user@example.com")).toBeInTheDocument();
+    });
+  });
+
+  it("adds selected calendars on save", async () => {
+    const addSharedCalendarSpy = jest
+      .spyOn(CalendarSlice, "addSharedCalendarAsync")
+      .mockImplementation((payload) => {
+        return () => Promise.resolve(payload) as any;
+      });
+
+    mockedSearchUsers.mockResolvedValueOnce([mockUser]);
+    mockedGetCalendars.mockResolvedValueOnce({
+      _embedded: {
+        "dav:calendar": [mockCalendar],
+      },
+    });
+
+    await act(async () => {
+      renderWithProviders(
+        <CalendarSearch anchorEl={null} open={true} onClose={mockOnClose} />,
+        preloadedState
+      );
+    });
+
+    const input = screen.getByRole("combobox");
+    await act(async () => {
+      userEvent.type(input, "Test");
+    });
+
+    const option = await screen.findByText("Test User");
+    await act(async () => {
+      fireEvent.click(option);
+    });
+
+    await waitFor(() => {
+      expect(screen.getByText("Test Calendar")).toBeInTheDocument();
+    });
+
+    const addButton = screen.getByRole("button", { name: /add/i });
+    await act(async () => {
+      fireEvent.click(addButton);
+    });
+
+    expect(addSharedCalendarSpy).toHaveBeenCalled();
+    expect(mockOnClose).toHaveBeenCalled();
+  });
+
+  it("does not add calendars that already exist", async () => {
+    const addSharedCalendarSpy = jest
+      .spyOn(CalendarSlice, "addSharedCalendarAsync")
+      .mockImplementation((payload) => {
+        return () => Promise.resolve(payload) as any;
+      });
+
+    const existingCalendar = {
+      ...mockCalendar,
+      _links: {
+        self: {
+          href: "/calendars/user1/cal1.json",
+        },
+      },
+    };
+
+    mockedSearchUsers.mockResolvedValueOnce([mockUser]);
+    mockedGetCalendars.mockResolvedValueOnce({
+      _embedded: {
+        "dav:calendar": [existingCalendar],
+      },
+    });
+
+    await act(async () => {
+      renderWithProviders(
+        <CalendarSearch anchorEl={null} open={true} onClose={mockOnClose} />,
+        preloadedState
+      );
+    });
+
+    const input = screen.getByRole("combobox");
+    await act(async () => {
+      userEvent.type(input, "Test");
+    });
+
+    const option = await screen.findByText("Test User");
+    await act(async () => {
+      fireEvent.click(option);
+    });
+
+    await waitFor(() => {
+      expect(
+        screen.getByText("No more Calendar for Test User")
+      ).toBeInTheDocument();
+    });
+
+    const addButton = screen.getByRole("button", { name: /add/i });
+    await act(async () => {
+      fireEvent.click(addButton);
+    });
+
+    expect(addSharedCalendarSpy).not.toHaveBeenCalled();
+  });
+
+  it("displays message when user has no publicly available calendars", async () => {
+    mockedSearchUsers.mockResolvedValueOnce([mockUser]);
+    mockedGetCalendars.mockResolvedValueOnce({});
+
+    await act(async () => {
+      renderWithProviders(
+        <CalendarSearch anchorEl={null} open={true} onClose={mockOnClose} />,
+        preloadedState
+      );
+    });
+
+    const input = screen.getByRole("combobox");
+    await act(async () => {
+      userEvent.type(input, "Test");
+    });
+
+    const option = await screen.findByText("Test User");
+    await act(async () => {
+      fireEvent.click(option);
+    });
+
+    await waitFor(() => {
+      expect(
+        screen.getByText("No publicly available calendars for Test User")
+      ).toBeInTheDocument();
+    });
+  });
+
+  it("changes calendar color", async () => {
+    mockedSearchUsers.mockResolvedValueOnce([mockUser]);
+    mockedGetCalendars.mockResolvedValueOnce({
+      _embedded: {
+        "dav:calendar": [mockCalendar],
+      },
+    });
+
+    await act(async () => {
+      renderWithProviders(
+        <CalendarSearch anchorEl={null} open={true} onClose={mockOnClose} />,
+        preloadedState
+      );
+    });
+
+    const input = screen.getByRole("combobox");
+    await act(async () => {
+      userEvent.type(input, "Test");
+    });
+
+    const option = await screen.findByText("Test User");
+    await act(async () => {
+      fireEvent.click(option);
+    });
+
+    await waitFor(() => {
+      expect(screen.getByText("Test Calendar")).toBeInTheDocument();
+    });
+
+    // ColorPicker would need to be interacted with based on its implementation
+    // This is a placeholder for color change interaction
+    const colorPicker = document.querySelector('[data-testid="color-picker"]');
+    if (colorPicker) {
+      await act(async () => {
+        fireEvent.click(colorPicker);
+      });
+    }
+  });
+
+  it("handles multiple calendars from the same user", async () => {
+    const secondCalendar = {
+      "dav:name": "Second Calendar",
+      "apple:color": "#00FF00",
+      _links: {
+        self: {
+          href: "/calendars/user123/cal2.json",
+        },
+      },
+    };
+
+    mockedSearchUsers.mockResolvedValueOnce([mockUser]);
+    mockedGetCalendars.mockResolvedValueOnce({
+      _embedded: {
+        "dav:calendar": [mockCalendar, secondCalendar],
+      },
+    });
+
+    await act(async () => {
+      renderWithProviders(
+        <CalendarSearch anchorEl={null} open={true} onClose={mockOnClose} />,
+        preloadedState
+      );
+    });
+
+    const input = screen.getByRole("combobox");
+    await act(async () => {
+      userEvent.type(input, "Test");
+    });
+
+    const option = await screen.findByText("Test User");
+    await act(async () => {
+      fireEvent.click(option);
+    });
+
+    await waitFor(() => {
+      expect(screen.getByText("Test Calendar")).toBeInTheDocument();
+      expect(screen.getByText("Second Calendar")).toBeInTheDocument();
+    });
+  });
+
+  it("does not call addSharedCalendarAsync when no calendars are selected", async () => {
+    const addSharedCalendarSpy = jest
+      .spyOn(CalendarSlice, "addSharedCalendarAsync")
+      .mockImplementation((payload) => {
+        return () => Promise.resolve(payload) as any;
+      });
+
+    await act(async () => {
+      renderWithProviders(
+        <CalendarSearch anchorEl={null} open={true} onClose={mockOnClose} />,
+        preloadedState
+      );
+    });
+
+    const addButton = screen.getByRole("button", { name: /add/i });
+    await act(async () => {
+      fireEvent.click(addButton);
+    });
+
+    expect(addSharedCalendarSpy).not.toHaveBeenCalled();
+  });
+
+  it("BUGFIX : handles calendar with no apple:color", async () => {
+    const mockCalendarNoColor = {
+      "dav:name": "Test Calendar",
+      _links: {
+        self: {
+          href: "/calendars/user123/cal1.json",
+        },
+      },
+    };
+    mockedSearchUsers.mockResolvedValueOnce([mockUser]);
+    mockedGetCalendars.mockResolvedValueOnce({
+      _embedded: {
+        "dav:calendar": [mockCalendarNoColor],
+      },
+    });
+
+    await act(async () => {
+      renderWithProviders(
+        <CalendarSearch anchorEl={null} open={true} onClose={mockOnClose} />,
+        preloadedState
+      );
+    });
+
+    const input = screen.getByRole("combobox");
+    await act(async () => {
+      userEvent.type(input, "Test");
+    });
+
+    const option = await screen.findByText("Test User");
+    await act(async () => {
+      fireEvent.click(option);
+    });
+
+    await waitFor(() => {
+      expect(mockedGetCalendars).toHaveBeenCalledWith(
+        "user123",
+        "sharedPublic=true&withRights=true"
+      );
+    });
+
+    await waitFor(() => {
+      expect(screen.getByText("Test Calendar")).toBeInTheDocument();
+      expect(screen.getByText("user@example.com")).toBeInTheDocument();
+    });
+  });
+});
diff --git a/src/components/Calendar/CalendarSearch.tsx b/src/components/Calendar/CalendarSearch.tsx
index 12ebed5..50c4472 100644
--- a/src/components/Calendar/CalendarSearch.tsx
+++ b/src/components/Calendar/CalendarSearch.tsx
@@ -16,7 +16,7 @@ import { addSharedCalendarAsync } from "../../features/Calendars/CalendarSlice";
 import { ColorPicker } from "./CalendarColorPicker";
 import { Calendars } from "../../features/Calendars/CalendarTypes";
 import { User, PeopleSearch } from "../Attendees/PeopleSearch";
-import { getAccessiblePair } from "./utils/calendarColorsUtils";
+import { defaultColors, getAccessiblePair } from "./utils/calendarColorsUtils";
 import { useTheme } from "@mui/material/styles";
 import { ResponsiveDialog } from "../Dialog";
 
@@ -54,10 +54,10 @@ function CalendarItem({
           src={cal.owner.avatarUrl}
           alt={cal.owner.email}
           style={{
-            border: `2px solid ${cal.cal["apple:color"] ?? "transparent"}`,
+            border: `2px solid ${cal.cal["apple:color"] || defaultColors[0]}`,
             boxShadow: cal.cal["apple:color"]
               ? `0 0 0 2px ${cal.cal["apple:color"]}`
-              : "none",
+              : `0 0 0 2px ${defaultColors[0]}`,
           }}
         />
         <Box>
@@ -75,8 +75,10 @@ function CalendarItem({
       <Box display="flex" alignItems="center" gap={1}>
         <ColorPicker
           selectedColor={{
-            light: cal.cal["apple:color"],
-            dark: getAccessiblePair(cal.cal["apple:color"], theme),
+            light: cal.cal["apple:color"] ?? defaultColors[0].light,
+            dark: cal.cal["apple:color"]
+              ? getAccessiblePair(cal.cal["apple:color"], theme)
+              : defaultColors[0].dark,
           }}
           onChange={onColorChange}
         />