diff --git a/deltachat-repl/src/cmdline.rs b/deltachat-repl/src/cmdline.rs
index 30f4c9185..28a166630 100644
--- a/deltachat-repl/src/cmdline.rs
+++ b/deltachat-repl/src/cmdline.rs
@@ -3,7 +3,7 @@ extern crate dirs;
 
 use std::path::Path;
 use std::str::FromStr;
-use std::time::{Duration, SystemTime};
+use std::time::Duration;
 
 use anyhow::{bail, ensure, Result};
 use deltachat::chat::{
diff --git a/src/blob.rs b/src/blob.rs
index da4d07376..eacd972f5 100644
--- a/src/blob.rs
+++ b/src/blob.rs
@@ -696,9 +696,8 @@ fn encoded_img_exceeds_bytes(
 
 #[cfg(test)]
 mod tests {
-    use anyhow::Result;
     use fs::File;
-    use image::{GenericImageView, Pixel};
+    use image::Pixel;
 
     use super::*;
     use crate::chat::{self, create_group_chat, ProtectionStatus};
diff --git a/src/chat.rs b/src/chat.rs
index 9f91f48f1..c3b7326a5 100644
--- a/src/chat.rs
+++ b/src/chat.rs
@@ -2,7 +2,6 @@
 
 use std::cmp;
 use std::collections::{HashMap, HashSet};
-use std::convert::{TryFrom, TryInto};
 use std::fmt;
 use std::path::{Path, PathBuf};
 use std::str::FromStr;
@@ -4468,9 +4467,8 @@ impl Context {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::chatlist::{get_archived_cnt, Chatlist};
+    use crate::chatlist::get_archived_cnt;
     use crate::constants::{DC_GCL_ARCHIVED_ONLY, DC_GCL_NO_SPECIALS};
-    use crate::contact::{Contact, ContactAddress};
     use crate::message::delete_msgs;
     use crate::receive_imf::receive_imf;
     use crate::test_utils::{sync, TestContext, TestContextManager};
diff --git a/src/config.rs b/src/config.rs
index 027ef083a..c124f08b0 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -773,12 +773,9 @@ fn get_config_keys_string() -> String {
 
 #[cfg(test)]
 mod tests {
-    use std::string::ToString;
-
     use num_traits::FromPrimitive;
 
     use super::*;
-    use crate::constants;
     use crate::test_utils::{sync, TestContext, TestContextManager};
 
     #[test]
diff --git a/src/contact.rs b/src/contact.rs
index 216a28b7e..131a5cd0c 100644
--- a/src/contact.rs
+++ b/src/contact.rs
@@ -2,7 +2,6 @@
 
 use std::cmp::Reverse;
 use std::collections::BinaryHeap;
-use std::convert::{TryFrom, TryInto};
 use std::fmt;
 use std::ops::Deref;
 use std::path::{Path, PathBuf};
diff --git a/src/context.rs b/src/context.rs
index feac1418f..b0c269e43 100644
--- a/src/context.rs
+++ b/src/context.rs
@@ -1343,20 +1343,14 @@ pub fn get_version_str() -> &'static str {
 
 #[cfg(test)]
 mod tests {
-    use std::time::Duration;
-
     use anyhow::Context as _;
     use strum::IntoEnumIterator;
     use tempfile::tempdir;
 
     use super::*;
-    use crate::chat::{
-        get_chat_contacts, get_chat_msgs, send_msg, set_muted, Chat, ChatId, MuteDuration,
-    };
+    use crate::chat::{get_chat_contacts, get_chat_msgs, send_msg, set_muted, Chat, MuteDuration};
     use crate::chatlist::Chatlist;
     use crate::constants::Chattype;
-    use crate::contact::ContactId;
-    use crate::message::{Message, Viewtype};
     use crate::mimeparser::SystemMessage;
     use crate::receive_imf::receive_imf;
     use crate::test_utils::{get_chat_msg, TestContext};
@@ -1583,14 +1577,14 @@ mod tests {
         let t = TestContext::new().await;
 
         let info = t.get_info().await.unwrap();
-        assert!(info.get("database_dir").is_some());
+        assert!(info.contains_key("database_dir"));
     }
 
     #[test]
     fn test_get_info_no_context() {
         let info = get_info();
-        assert!(info.get("deltachat_core_version").is_some());
-        assert!(info.get("database_dir").is_none());
+        assert!(info.contains_key("deltachat_core_version"));
+        assert!(!info.contains_key("database_dir"));
         assert_eq!(info.get("level").unwrap(), "awesome");
     }
 
diff --git a/src/download.rs b/src/download.rs
index 1d031a81e..7919722b4 100644
--- a/src/download.rs
+++ b/src/download.rs
@@ -253,7 +253,6 @@ mod tests {
     use super::*;
     use crate::chat::{get_chat_msgs, send_msg};
     use crate::ephemeral::Timer;
-    use crate::message::Viewtype;
     use crate::receive_imf::receive_imf_from_inbox;
     use crate::test_utils::TestContext;
 
diff --git a/src/ephemeral.rs b/src/ephemeral.rs
index 719243f3e..9146698c1 100644
--- a/src/ephemeral.rs
+++ b/src/ephemeral.rs
@@ -64,7 +64,7 @@
 
 use std::cmp::max;
 use std::collections::BTreeSet;
-use std::convert::{TryFrom, TryInto};
+use std::fmt;
 use std::num::ParseIntError;
 use std::str::FromStr;
 use std::time::{Duration, UNIX_EPOCH};
@@ -131,9 +131,9 @@ impl Default for Timer {
     }
 }
 
-impl ToString for Timer {
-    fn to_string(&self) -> String {
-        self.to_u32().to_string()
+impl fmt::Display for Timer {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{}", self.to_u32())
     }
 }
 
diff --git a/src/html.rs b/src/html.rs
index 5af221b70..37798bc57 100644
--- a/src/html.rs
+++ b/src/html.rs
@@ -13,7 +13,7 @@ use std::pin::Pin;
 use anyhow::{Context as _, Result};
 use base64::Engine as _;
 use futures::future::FutureExt;
-use lettre_email::mime::{self, Mime};
+use lettre_email::mime::Mime;
 use lettre_email::PartBuilder;
 use mailparse::ParsedContentType;
 
@@ -67,7 +67,7 @@ enum MimeMultipartType {
 /// and checks and returns the rough mime-type.
 fn get_mime_multipart_type(ctype: &ParsedContentType) -> MimeMultipartType {
     let mimetype = ctype.mimetype.to_lowercase();
-    if mimetype.starts_with("multipart") && ctype.params.get("boundary").is_some() {
+    if mimetype.starts_with("multipart") && ctype.params.contains_key("boundary") {
         MimeMultipartType::Multiple
     } else if mimetype == "message/rfc822" {
         MimeMultipartType::Message
diff --git a/src/imap.rs b/src/imap.rs
index 61bde65f0..333488ae3 100644
--- a/src/imap.rs
+++ b/src/imap.rs
@@ -2414,9 +2414,6 @@ async fn add_all_recipients_as_contacts(
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::chat::ChatId;
-    use crate::config::Config;
-    use crate::contact::Contact;
     use crate::test_utils::TestContext;
 
     #[test]
diff --git a/src/imex.rs b/src/imex.rs
index bab2732eb..e1887236c 100644
--- a/src/imex.rs
+++ b/src/imex.rs
@@ -824,7 +824,6 @@ mod tests {
     use tokio::task;
 
     use super::*;
-    use crate::key;
     use crate::pgp::{split_armored_data, HEADER_AUTOCRYPT, HEADER_SETUPCODE};
     use crate::stock_str::StockMessage;
     use crate::test_utils::{alice_keypair, TestContext, TestContextManager};
@@ -1105,7 +1104,7 @@ mod tests {
         let (typ, headers, base64) = split_armored_data(&buf_1).unwrap();
         assert_eq!(typ, BlockType::Message);
         assert!(S_EM_SETUPCODE.starts_with(headers.get(HEADER_SETUPCODE).unwrap()));
-        assert!(headers.get(HEADER_AUTOCRYPT).is_none());
+        assert!(!headers.contains_key(HEADER_AUTOCRYPT));
 
         assert!(!base64.is_empty());
 
@@ -1119,7 +1118,7 @@ mod tests {
 
         assert_eq!(typ, BlockType::PrivateKey);
         assert_eq!(headers.get(HEADER_AUTOCRYPT), Some(&"mutual".to_string()));
-        assert!(headers.get(HEADER_SETUPCODE).is_none());
+        assert!(!headers.contains_key(HEADER_SETUPCODE));
     }
 
     /// Tests that Autocrypt Setup Message encrypted with "plaintext" algorithm cannot be
diff --git a/src/imex/transfer.rs b/src/imex/transfer.rs
index ee388e66c..a685c35bb 100644
--- a/src/imex/transfer.rs
+++ b/src/imex/transfer.rs
@@ -597,7 +597,6 @@ mod tests {
     use std::time::Duration;
 
     use crate::chat::{get_chat_msgs, send_msg, ChatItem};
-    use crate::message::{Message, Viewtype};
     use crate::test_utils::TestContextManager;
 
     use super::*;
diff --git a/src/location.rs b/src/location.rs
index e5ce15a2e..95e6a7ffd 100644
--- a/src/location.rs
+++ b/src/location.rs
@@ -1,6 +1,5 @@
 //! Location handling.
 
-use std::convert::TryFrom;
 use std::time::Duration;
 
 use anyhow::{ensure, Context as _, Result};
diff --git a/src/mimefactory.rs b/src/mimefactory.rs
index 01d353b9e..6eebceafa 100644
--- a/src/mimefactory.rs
+++ b/src/mimefactory.rs
@@ -1,13 +1,12 @@
 //! # MIME message production.
 
 use std::collections::HashSet;
-use std::convert::TryInto;
 
 use anyhow::{bail, ensure, Context as _, Result};
 use base64::Engine as _;
 use chrono::TimeZone;
 use format_flowed::{format_flowed, format_flowed_quote};
-use lettre_email::{mime, Address, Header, MimeMultipartType, PartBuilder};
+use lettre_email::{Address, Header, MimeMultipartType, PartBuilder};
 use tokio::fs;
 
 use crate::blob::BlobObject;
diff --git a/src/mimeparser.rs b/src/mimeparser.rs
index 9d6b7a9d4..b4052ae08 100644
--- a/src/mimeparser.rs
+++ b/src/mimeparser.rs
@@ -10,7 +10,7 @@ use std::str;
 use anyhow::{bail, Context as _, Result};
 use deltachat_derive::{FromSql, ToSql};
 use format_flowed::unformat_flowed;
-use lettre_email::mime::{self, Mime};
+use lettre_email::mime::Mime;
 use mailparse::{addrparse_header, DispositionType, MailHeader, MailHeaderMap, SingleInfo};
 
 use crate::aheader::{Aheader, EncryptPreference};
@@ -836,7 +836,7 @@ impl MimeMessage {
             let mimetype = mail.ctype.mimetype.to_lowercase();
 
             let m = if mimetype.starts_with("multipart") {
-                if mail.ctype.params.get("boundary").is_some() {
+                if mail.ctype.params.contains_key("boundary") {
                     MimeS::Multiple
                 } else {
                     MimeS::Single
@@ -2262,7 +2262,7 @@ mod tests {
         chat,
         chatlist::Chatlist,
         constants::{Blocked, DC_DESIRED_TEXT_LEN, DC_ELLIPSIS},
-        message::{Message, MessageState, MessengerMessage},
+        message::MessengerMessage,
         receive_imf::receive_imf,
         test_utils::{TestContext, TestContextManager},
         tools::time,
diff --git a/src/param.rs b/src/param.rs
index 041215a62..d035d2d11 100644
--- a/src/param.rs
+++ b/src/param.rs
@@ -455,7 +455,6 @@ mod tests {
     use std::path::Path;
     use std::str::FromStr;
 
-    use anyhow::Result;
     use tokio::fs;
 
     use super::*;
diff --git a/src/qr.rs b/src/qr.rs
index 9dcc2b753..7081b1d1b 100644
--- a/src/qr.rs
+++ b/src/qr.rs
@@ -821,8 +821,6 @@ fn normalize_address(addr: &str) -> Result<String> {
 
 #[cfg(test)]
 mod tests {
-    use anyhow::Result;
-
     use super::*;
     use crate::aheader::EncryptPreference;
     use crate::chat::{create_group_chat, ProtectionStatus};
diff --git a/src/qr/dclogin_scheme.rs b/src/qr/dclogin_scheme.rs
index 01ae8203e..965e288c4 100644
--- a/src/qr/dclogin_scheme.rs
+++ b/src/qr/dclogin_scheme.rs
@@ -268,7 +268,7 @@ pub(crate) async fn configure_from_login_qr(
 
 #[cfg(test)]
 mod test {
-    use anyhow::{self, bail};
+    use anyhow::bail;
 
     use super::{decode_login, LoginOptions};
     use crate::{login_param::CertificateChecks, provider::Socket, qr::Qr};
diff --git a/src/quota.rs b/src/quota.rs
index 45e929d7a..620c3a5dc 100644
--- a/src/quota.rs
+++ b/src/quota.rs
@@ -155,10 +155,6 @@ impl Context {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::quota::{
-        QUOTA_ALLCLEAR_PERCENTAGE, QUOTA_ERROR_THRESHOLD_PERCENTAGE,
-        QUOTA_WARN_THRESHOLD_PERCENTAGE,
-    };
 
     #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
     async fn test_needs_quota_warning() -> Result<()> {
diff --git a/src/receive_imf.rs b/src/receive_imf.rs
index e289e6efe..4383b5f0c 100644
--- a/src/receive_imf.rs
+++ b/src/receive_imf.rs
@@ -1,7 +1,6 @@
 //! Internet Message Format reception pipeline.
 
 use std::collections::HashSet;
-use std::convert::TryFrom;
 
 use anyhow::{Context as _, Result};
 use mailparse::{parse_mail, SingleInfo};
diff --git a/src/receive_imf/tests.rs b/src/receive_imf/tests.rs
index 708ff2cbf..f08c54252 100644
--- a/src/receive_imf/tests.rs
+++ b/src/receive_imf/tests.rs
@@ -1,19 +1,16 @@
 use tokio::fs;
 
 use super::*;
-use crate::aheader::EncryptPreference;
-use crate::chat::{self, get_chat_msgs, ChatItem, ChatVisibility};
 use crate::chat::{
     add_contact_to_chat, add_to_chat_contacts_table, create_group_chat, get_chat_contacts,
-    is_contact_in_chat, remove_contact_from_chat, send_text_msg,
+    get_chat_msgs, is_contact_in_chat, remove_contact_from_chat, send_text_msg, ChatItem,
+    ChatVisibility,
 };
 use crate::chatlist::Chatlist;
-use crate::config::Config;
 use crate::constants::{DC_GCL_FOR_FORWARDING, DC_GCL_NO_SPECIALS};
-use crate::download::{DownloadState, MIN_DOWNLOAD_LIMIT};
+use crate::download::MIN_DOWNLOAD_LIMIT;
 use crate::imap::prefetch_should_download;
 use crate::imex::{imex, ImexMode};
-use crate::message::{self, Message};
 use crate::test_utils::{get_chat_msg, TestContext, TestContextManager};
 
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
diff --git a/src/securejoin.rs b/src/securejoin.rs
index 2eb66b634..355205f73 100644
--- a/src/securejoin.rs
+++ b/src/securejoin.rs
@@ -1,7 +1,5 @@
 //! Verified contact protocol implementation as [specified by countermitm project](https://securejoin.readthedocs.io/en/latest/new.html#setup-contact-protocol).
 
-use std::convert::TryFrom;
-
 use anyhow::{bail, Context as _, Error, Result};
 use percent_encoding::{utf8_percent_encode, AsciiSet, NON_ALPHANUMERIC};
 
@@ -757,12 +755,10 @@ fn encrypted_and_signed(
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::chat;
-    use crate::chat::{remove_contact_from_chat, ProtectionStatus};
+    use crate::chat::remove_contact_from_chat;
     use crate::chatlist::Chatlist;
     use crate::constants::Chattype;
     use crate::contact::ContactAddress;
-    use crate::peerstate::Peerstate;
     use crate::receive_imf::receive_imf;
     use crate::stock_str::chat_protection_enabled;
     use crate::test_utils::get_chat_msg;
diff --git a/src/securejoin/qrinvite.rs b/src/securejoin/qrinvite.rs
index 20f5abf0e..fc89ca9ea 100644
--- a/src/securejoin/qrinvite.rs
+++ b/src/securejoin/qrinvite.rs
@@ -4,8 +4,6 @@
 //! with it rather hard, so here we have a wrapper type that specifically deals with Secure-Join
 //! QR-codes so that the Secure-Join code can have more guarantees when dealing with this.
 
-use std::convert::TryFrom;
-
 use anyhow::{bail, Error, Result};
 
 use crate::contact::ContactId;
diff --git a/src/sql.rs b/src/sql.rs
index 2909eab2d..1f5055cce 100644
--- a/src/sql.rs
+++ b/src/sql.rs
@@ -1,11 +1,10 @@
 //! # SQLite wrapper.
 
 use std::collections::{HashMap, HashSet};
-use std::convert::TryFrom;
 use std::path::{Path, PathBuf};
 
 use anyhow::{bail, Context as _, Result};
-use rusqlite::{self, config::DbConfig, types::ValueRef, Connection, OpenFlags, Row};
+use rusqlite::{config::DbConfig, types::ValueRef, Connection, OpenFlags, Row};
 use tokio::sync::{Mutex, MutexGuard, RwLock};
 
 use crate::blob::BlobObject;
@@ -1015,7 +1014,6 @@ mod tests {
     use async_channel as channel;
 
     use super::*;
-    use crate::config::Config;
     use crate::{test_utils::TestContext, EventType};
 
     #[test]
diff --git a/src/stock_str.rs b/src/stock_str.rs
index 70853eb3f..d957640d5 100644
--- a/src/stock_str.rs
+++ b/src/stock_str.rs
@@ -1421,7 +1421,6 @@ mod tests {
 
     use super::*;
     use crate::chat::delete_and_reset_all_device_msgs;
-    use crate::chat::Chat;
     use crate::chatlist::Chatlist;
     use crate::test_utils::TestContext;
 
diff --git a/src/sync.rs b/src/sync.rs
index c43b70d68..7cc539a28 100644
--- a/src/sync.rs
+++ b/src/sync.rs
@@ -1,7 +1,6 @@
 //! # Synchronize items between devices.
 
 use anyhow::Result;
-use lettre_email::mime::{self};
 use lettre_email::PartBuilder;
 use serde::{Deserialize, Serialize};
 
@@ -321,11 +320,9 @@ mod tests {
     use anyhow::bail;
 
     use super::*;
-    use crate::chat::Chat;
     use crate::chatlist::Chatlist;
     use crate::contact::{Contact, Origin};
     use crate::test_utils::TestContext;
-    use crate::token::Namespace;
     use crate::tools::SystemTime;
 
     #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
diff --git a/src/tools.rs b/src/tools.rs
index 9f8da2a9d..02530efba 100644
--- a/src/tools.rs
+++ b/src/tools.rs
@@ -1079,7 +1079,7 @@ DKIM Results: Passed=true, Works=true, Allow_Keychange=true";
         assert_eq!(EmailAddress::new("@d.tt").is_ok(), false);
     }
 
-    use chrono::{NaiveDate, NaiveDateTime, NaiveTime};
+    use chrono::NaiveDate;
     use proptest::prelude::*;
 
     use crate::chatlist::Chatlist;
diff --git a/src/webxdc.rs b/src/webxdc.rs
index 74c3fd9a0..77808cc92 100644
--- a/src/webxdc.rs
+++ b/src/webxdc.rs
@@ -20,7 +20,6 @@ use std::path::Path;
 use anyhow::{anyhow, bail, ensure, format_err, Context as _, Result};
 
 use deltachat_derive::FromSql;
-use lettre_email::mime;
 use lettre_email::PartBuilder;
 use serde::{Deserialize, Serialize};
 use serde_json::Value;