Add FindAssignable method to User

cloud/user.go

@@ -257,6 +257,22 @@ func WithAccountId(accountId string) UserSearchF {
 	}
 }
 
+// WithIssueKey sets the issue key to search
+func WithIssueKey(issueKey string) UserSearchF {
+	return func(s UserSearch) UserSearch {
+		s = append(s, UserSearchParam{name: "issueKey", value: issueKey})
+		return s
+	}
+}
+
+// WithProject sets the project to search
+func WithProject(project string) UserSearchF {
+	return func(s UserSearch) UserSearch {
+		s = append(s, UserSearchParam{name: "project", value: project})
+		return s
+	}
+}
+
 // WithProperty sets the property (Property keys are specified by path) to search
 func WithProperty(property string) UserSearchF {
 	return func(s UserSearch) UserSearch {
@@ -301,3 +317,35 @@ func (s *UserService) Find(ctx context.Context, property string, tweaks ...UserS
 	}
 	return users, resp, nil
 }
+
+// FindAssignable gets all assignable users for an issue:
+//
+//  Accepts username, project, issueKey, startAt, and maxResults as tweaks
+//
+// https://docs.atlassian.com/software/jira/docs/api/REST/1000.1568.0/#api/2/user-findAssignableUsers
+//
+// TODO Double check this method if this works as expected, is using the latest API and the response is complete
+// This double check effort is done for v2 - Remove this two lines if this is completed.
+func (s *UserService) FindAssignable(ctx context.Context, tweaks ...UserSearchF) ([]User, *Response, error) {
+	search := []UserSearchParam{}
+	for _, f := range tweaks {
+		search = f(search)
+	}
+
+	var queryString = ""
+	for _, param := range search {
+		queryString += param.name + "=" + param.value + "&"
+	}
+	apiEndpoint := fmt.Sprintf("/rest/api/2/user/assignable/search?%s", queryString)
+	req, err := s.client.NewRequest(ctx, http.MethodGet, apiEndpoint, nil)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	users := []User{}
+	resp, err := s.client.Do(req, &users)
+	if err != nil {
+		return nil, resp, NewJiraError(resp, err)
+	}
+	return users, resp, nil
+}

cloud/user_test.go

@@ -282,3 +282,26 @@ func TestUserService_Find_SuccessParams(t *testing.T) {
 		t.Error("Expected user. User is nil")
 	}
 }
+
+func TestUserService_FindAssignable_Success(t *testing.T) {
+	setup()
+	defer teardown()
+	testMux.HandleFunc("/rest/api/2/user/assignable/search", func(w http.ResponseWriter, r *http.Request) {
+		testMethod(t, r, http.MethodGet)
+		testRequestURL(t, r, "/rest/api/2/user/assignable/[email protected]&project=DAPHNE&issueKey=DAPHNE-11&maxResults=100&startAt=0")
+
+		fmt.Fprint(w, `[{"self":"http://www.example.com/jira/rest/api/2/user?accountId=000000000000000000000000","key":"fred",
+        "name":"fred","emailAddress":"[email protected]","avatarUrls":{"48x48":"http://www.example.com/jira/secure/useravatar?size=large&ownerId=fred",
+        "24x24":"http://www.example.com/jira/secure/useravatar?size=small&ownerId=fred","16x16":"http://www.example.com/jira/secure/useravatar?size=xsmall&ownerId=fred",
+        "32x32":"http://www.example.com/jira/secure/useravatar?size=medium&ownerId=fred"},"displayName":"Fred F. User","active":true,"timeZone":"Australia/Sydney","groups":{"size":3,"items":[
+        {"name":"jira-user","self":"http://www.example.com/jira/rest/api/2/group?groupname=jira-user"},{"name":"jira-admin",
+        "self":"http://www.example.com/jira/rest/api/2/group?groupname=jira-admin"},{"name":"important","self":"http://www.example.com/jira/rest/api/2/group?groupname=important"
+        }]},"applicationRoles":{"size":1,"items":[]},"expand":"groups,applicationRoles"}]`)
+	})
+
+	if user, _, err := testClient.User.FindAssignable(context.Background(), WithUsername("[email protected]"), WithProject("DAPHNE"), WithIssueKey("DAPHNE-11"), WithMaxResults(100), WithStartAt(0)); err != nil {
+		t.Errorf("Error given: %s", err)
+	} else if user == nil {
+		t.Error("Expected user. User is nil")
+	}
+}