diff --git a/Cargo.lock b/Cargo.lock
index a5f00db..2c6c3c9 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -31,6 +31,15 @@ dependencies = [
  "zerocopy",
 ]
 
+[[package]]
+name = "aho-corasick"
+version = "1.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8e60d3430d3a69478ad0993f19238d2df97c507009a52b3c10addcd7f6bcb916"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "anstream"
 version = "0.6.14"
@@ -86,6 +95,16 @@ version = "1.0.86"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b3d1d046238990b9cf5bcde22a3fb3584ee5cf65fb2765f454ed428c7a0063da"
 
+[[package]]
+name = "assert-json-diff"
+version = "2.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "47e4f2b81832e72834d7518d8487a0396a28cc408186a2e8854c0f98011faf12"
+dependencies = [
+ "serde",
+ "serde_json",
+]
+
 [[package]]
 name = "atomic-waker"
 version = "1.1.2"
@@ -137,6 +156,12 @@ version = "3.16.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "79296716171880943b8470b5f8d03aa55eb2e645a4874bdbb28adb49162e012c"
 
+[[package]]
+name = "byteorder"
+version = "1.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1fd0f2584146f6f2ef48085050886acf353beff7305ebd1ae69500e27c67f64b"
+
 [[package]]
 name = "bytes"
 version = "1.6.1"
@@ -201,6 +226,16 @@ version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0b6a852b24ab71dffc585bcb46eaf7959d175cb865a7152e35b348d1b2960422"
 
+[[package]]
+name = "colored"
+version = "2.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cbf2150cce219b664a8a70df7a1f933836724b503f8a413af9365b4dcc4d90b8"
+dependencies = [
+ "lazy_static",
+ "windows-sys 0.48.0",
+]
+
 [[package]]
 name = "const-random"
 version = "0.1.18"
@@ -500,6 +535,12 @@ version = "1.9.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0fcc0b4a115bf80b728eb8ea024ad5bd707b615bfed49e0665b6e0f86fd082d9"
 
+[[package]]
+name = "httpdate"
+version = "1.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "df3b46402a9d5adb4c86a0cf463f42e19994e3ee891101b1841f30a545cb49a9"
+
 [[package]]
 name = "hyper"
 version = "1.4.1"
@@ -513,6 +554,7 @@ dependencies = [
  "http",
  "http-body",
  "httparse",
+ "httpdate",
  "itoa",
  "pin-project-lite",
  "smallvec",
@@ -638,6 +680,12 @@ dependencies = [
  "wasm-bindgen",
 ]
 
+[[package]]
+name = "lazy_static"
+version = "1.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bbd2bcb4c963f2ddae06a2efc7e9f3591312473c50c6685e1f298068316e66fe"
+
 [[package]]
 name = "libc"
 version = "0.2.155"
@@ -650,6 +698,16 @@ version = "0.4.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "78b3ae25bc7c8c38cec158d1f2757ee79e9b3740fbc7ccf0e59e4b08d793fa89"
 
+[[package]]
+name = "lock_api"
+version = "0.4.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "07af8b9cdd281b7915f413fa73f29ebd5d55d0d3f0155584dade1ff18cea1b17"
+dependencies = [
+ "autocfg",
+ "scopeguard",
+]
+
 [[package]]
 name = "log"
 version = "0.4.22"
@@ -689,6 +747,30 @@ dependencies = [
  "windows-sys 0.52.0",
 ]
 
+[[package]]
+name = "mockito"
+version = "1.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "09b34bd91b9e5c5b06338d392463e1318d683cf82ec3d3af4014609be6e2108d"
+dependencies = [
+ "assert-json-diff",
+ "bytes",
+ "colored",
+ "futures-util",
+ "http",
+ "http-body",
+ "http-body-util",
+ "hyper",
+ "hyper-util",
+ "log",
+ "rand",
+ "regex",
+ "serde_json",
+ "serde_urlencoded",
+ "similar",
+ "tokio",
+]
+
 [[package]]
 name = "native-tls"
 version = "0.2.12"
@@ -774,6 +856,29 @@ dependencies = [
  "vcpkg",
 ]
 
+[[package]]
+name = "parking_lot"
+version = "0.12.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f1bf18183cf54e8d6059647fc3063646a1801cf30896933ec2311622cc4b9a27"
+dependencies = [
+ "lock_api",
+ "parking_lot_core",
+]
+
+[[package]]
+name = "parking_lot_core"
+version = "0.9.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1e401f977ab385c9e4e3ab30627d6f26d00e2c73eef317493c4ec6d468726cf8"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "redox_syscall",
+ "smallvec",
+ "windows-targets 0.52.6",
+]
+
 [[package]]
 name = "percent-encoding"
 version = "2.3.1"
@@ -818,6 +923,15 @@ version = "0.3.30"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d231b230927b5e4ad203db57bbcbee2802f6bce620b1e4a9024a07d94e2907ec"
 
+[[package]]
+name = "ppv-lite86"
+version = "0.2.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "77957b295656769bb8ad2b6a6b09d897d94f05c41b069aede1fcdaa675eaea04"
+dependencies = [
+ "zerocopy",
+]
+
 [[package]]
 name = "proc-macro2"
 version = "1.0.86"
@@ -836,6 +950,36 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "rand"
+version = "0.8.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "34af8d1a0e25924bc5b7c43c079c942339d8f0a8b57c39049bef581b46327404"
+dependencies = [
+ "libc",
+ "rand_chacha",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_chacha"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e6c10a63a0fa32252be49d21e7709d4d4baf8d231c2dbce1eaa8141b9b127d88"
+dependencies = [
+ "ppv-lite86",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_core"
+version = "0.6.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ec0be4795e2f6a28069bec0b5ff3e2ac9bafc99e6a9a7dc3547996c5c816922c"
+dependencies = [
+ "getrandom",
+]
+
 [[package]]
 name = "rayon"
 version = "1.10.0"
@@ -856,6 +1000,44 @@ dependencies = [
  "crossbeam-utils",
 ]
 
+[[package]]
+name = "redox_syscall"
+version = "0.5.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2a908a6e00f1fdd0dfd9c0eb08ce85126f6d8bbda50017e74bc4a4b7d4a926a4"
+dependencies = [
+ "bitflags 2.6.0",
+]
+
+[[package]]
+name = "regex"
+version = "1.10.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4219d74c6b67a3654a9fbebc4b419e22126d13d2f3c4a07ee0cb61ff79a79619"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-automata",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-automata"
+version = "0.4.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "38caf58cc5ef2fed281f89292ef23f6365465ed9a41b7a7754eb4e26496c92df"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-syntax"
+version = "0.8.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7a66a03ae7c801facd77a29370b4faec201768915ac14a721ba36f20bc9c209b"
+
 [[package]]
 name = "reqwest"
 version = "0.12.5"
@@ -1018,6 +1200,12 @@ dependencies = [
  "windows-sys 0.52.0",
 ]
 
+[[package]]
+name = "scopeguard"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "94143f37725109f92c262ed2cf5e59bce7498c01bcc1502d7b9afe439a4e9f49"
+
 [[package]]
 name = "security-framework"
 version = "2.11.1"
@@ -1107,6 +1295,12 @@ dependencies = [
  "unsafe-libyaml",
 ]
 
+[[package]]
+name = "similar"
+version = "2.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1de1d4f81173b03af4c0cbed3c898f6bff5b870e4a7f5d6f4057d62a7a4b686e"
+
 [[package]]
 name = "slab"
 version = "0.4.9"
@@ -1179,6 +1373,7 @@ dependencies = [
  "clap",
  "csv",
  "itertools",
+ "mockito",
  "rayon",
  "reqwest",
  "rhai",
@@ -1302,6 +1497,7 @@ dependencies = [
  "bytes",
  "libc",
  "mio",
+ "parking_lot",
  "pin-project-lite",
  "socket2",
  "windows-sys 0.52.0",
@@ -1744,6 +1940,7 @@ version = "0.7.35"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1b9b4fd18abc82b8136838da5d50bae7bdea537c574d8dc1a34ed098d6c166f0"
 dependencies = [
+ "byteorder",
  "zerocopy-derive",
 ]
 
diff --git a/Cargo.toml b/Cargo.toml
index 91486c4..37f5675 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -23,6 +23,9 @@ csv = "1.3.0"
 itertools = "0.13.0"
 rhai = { version = "1.19.0", features = ["serde", "sync"] }
 
+[dev-dependencies]
+mockito = "1.5.0"
+
 [profile.release]
 lto = true          # Enable link-time optimization
 codegen-units = 1   # Reduce number of codegen units to increase optimizations
diff --git a/src/api/mod.rs b/src/api/mod.rs
index 5d18bf9..50f98b9 100644
--- a/src/api/mod.rs
+++ b/src/api/mod.rs
@@ -501,8 +501,9 @@ pub type Entity = serde_json::Map<String, serde_json::Value>;
 
 #[cfg(test)]
 mod tests {
-    use crate::api::CurrencyList;
-    use crate::api::IsoLanguageList;
+    use super::*;
+    use crate::config_file::Credentials;
+    use mockito::ServerGuard;
     use std::collections::HashMap;
 
     #[test]
@@ -558,4 +559,95 @@ mod tests {
         );
         assert_eq!(currency_list.get_currency_id_by_iso_code("GBP"), "");
     }
+
+    #[test]
+    fn test_sw_client_auth() {
+        let mut server = mockito::Server::new();
+
+        let base_url = server.url();
+        let credentials = Credentials {
+            base_url,
+            access_key_id: "access_key_id".to_string(),
+            access_key_secret: "access_key_secret".to_string(),
+        };
+
+        let mock = server
+            .mock("POST", "/api/oauth/token")
+            .match_header("content-type", "application/json")
+            .match_body(mockito::Matcher::Json(
+                serde_json::to_value(&AuthBody {
+                    grant_type: "client_credentials".to_string(),
+                    client_id: credentials.access_key_id.clone(),
+                    client_secret: credentials.access_key_secret.clone(),
+                })
+                .unwrap(),
+            ))
+            .with_header("content-type", "application/json")
+            .with_body(
+                r#"{
+                "access_token": "access_token"
+            }"#,
+            )
+            .create();
+
+        // client new also authenticates
+        let client = SwClient::new(credentials).unwrap();
+        mock.assert();
+
+        assert_eq!(client.access_token.lock().unwrap().as_str(), "access_token");
+    }
+
+    fn create_shopware_mock_server() -> (ServerGuard, SwClient) {
+        let mut server = mockito::Server::new();
+
+        let base_url = server.url();
+        let credentials = Credentials {
+            base_url,
+            access_key_id: "access_key_id".to_string(),
+            access_key_secret: "access_key_secret".to_string(),
+        };
+
+        let mock = server
+            .mock("POST", "/api/oauth/token")
+            .match_header("content-type", "application/json")
+            .match_body(mockito::Matcher::Json(
+                serde_json::to_value(&AuthBody {
+                    grant_type: "client_credentials".to_string(),
+                    client_id: credentials.access_key_id.clone(),
+                    client_secret: credentials.access_key_secret.clone(),
+                })
+                .unwrap(),
+            ))
+            .with_header("content-type", "application/json")
+            .with_body(
+                r#"{
+                "access_token": "access_token"
+            }"#,
+            )
+            .create();
+
+        let client = SwClient::new(credentials).unwrap();
+        mock.assert();
+        (server, client)
+    }
+
+    #[test]
+    fn test_sw_client_entity_schema() {
+        let (mut server, client) = create_shopware_mock_server();
+
+        let mock = server
+            .mock("GET", "/api/_info/entity-schema.json")
+            .with_header("content-type", "application/json")
+            .with_body_from_file("./fixtures/entity-schema-2024-08-01.json")
+            .create();
+
+        let schema = client.entity_schema().unwrap();
+        mock.assert();
+
+        let expected_schema: Entity = serde_json::from_str(
+            &std::fs::read_to_string("./fixtures/entity-schema-2024-08-01.json").unwrap(),
+        )
+        .unwrap();
+        assert_eq!(schema, expected_schema);
+    }
 }