diff --git a/packages/sdk/test/test-utils/customMatchers.ts b/packages/sdk/test/test-utils/customMatchers.ts
index aeedacaff1..ddd65e7ef4 100644
--- a/packages/sdk/test/test-utils/customMatchers.ts
+++ b/packages/sdk/test/test-utils/customMatchers.ts
@@ -1,5 +1,5 @@
 import { printExpected, printReceived } from 'jest-matcher-utils'
-import isFunction from 'lodash/isFunction'
+import { isFunction, isObject } from 'lodash'
 import { StreamrClientError, StreamrClientErrorCode } from './../../src/StreamrClientError'
 
 interface PartialStreamrClientError {
@@ -18,8 +18,8 @@ declare global {
     }
 }
 
-const formErrorMessage = (description: string, expected: string, actual: string): string => {
-    return `${description}\nExpected: ${printExpected(expected)}\nReceived: ${printReceived(actual)}`
+const formErrorMessage = (field: keyof StreamrClientError, expected: string, actual: string): string => {
+    return `StreamrClientError ${field} values don't match:\nExpected: ${printExpected(expected)}\nReceived: ${printReceived(actual)}`
 }
 
 const toThrowStreamrError = (
@@ -43,13 +43,14 @@ const toThrowStreamrError = (
 
     const messages: string[] = []
     if (!(actualError instanceof StreamrClientError)) {
-        messages.push(formErrorMessage('Class name', 'StreamrClientError', actualError.constructor.name))
+        const received = isObject(actualError) ? actualError.constructor.name : actualError
+        messages.push(`Not an instance of StreamrClientError:\nReceived: ${printReceived(received)}`)
     } else {
         if (actualError.code !== expectedError.code) {
-            messages.push(formErrorMessage('StreamrClientError.code', expectedError.code, actualError.code))
+            messages.push(formErrorMessage('code', expectedError.code, actualError.code))
         }
         if ((expectedError.message !== undefined) && (actualError.message !== expectedError.message)) {
-            messages.push(formErrorMessage('StreamrClientError.message', expectedError.message, actualError.message))
+            messages.push(formErrorMessage('message', expectedError.message, actualError.message))
         }
     }
     if (messages.length > 0) {
@@ -60,7 +61,7 @@ const toThrowStreamrError = (
     } else {
         return {
             pass: true,
-            message: () => `Expected not to throw ${printReceived('StreamrClientError')}`
+            message: () => `Expected not to throw StreamrClientError}`
         }
     }
 }
diff --git a/packages/sdk/test/unit/customMatchers.test.ts b/packages/sdk/test/unit/customMatchers.test.ts
new file mode 100644
index 0000000000..e854ddc2ad
--- /dev/null
+++ b/packages/sdk/test/unit/customMatchers.test.ts
@@ -0,0 +1,59 @@
+import { StreamrClientError } from '../../src/StreamrClientError'
+
+describe('custom matchers', () => {
+
+    describe('toThrowStreamrError', () => {
+
+        it('happy path', () => {
+            const error = new StreamrClientError('Foobar', 'UNKNOWN_ERROR')
+            expect(() => {
+                throw error
+            }).toThrowStreamrError({
+                code: error.code,
+                message: error.message
+            })
+        })
+
+        describe('error message', () => {
+
+            it('field', () => {
+                const actual = new StreamrClientError('Foobar', 'UNKNOWN_ERROR')
+                expect(() => {
+                    expect(() => { throw actual }).toThrowStreamrError({
+                        message: 'Foobar',
+                        code: 'UNSUPPORTED_OPERATION'
+                    })
+                }).toThrow('StreamrClientError code values don\'t match')
+            })
+
+            it('unexpected class', () => {
+                // eslint-disable-next-line @typescript-eslint/no-extraneous-class
+                class TestClass {}
+                expect(() => {
+                    // eslint-disable-next-line @typescript-eslint/only-throw-error
+                    expect(() => { throw new TestClass() }).toThrowStreamrError({
+                        message: 'Foobar',
+                        code: 'UNSUPPORTED_OPERATION'
+                    })
+                }).toThrow('Not an instance of StreamrClientError:\nReceived: "TestClass"')
+            })
+
+            it('unexpected primitive', () => {
+                expect(() => {
+                    // eslint-disable-next-line @typescript-eslint/only-throw-error
+                    expect(() => { throw 'mock-error' }).toThrowStreamrError({
+                        message: 'Foobar',
+                        code: 'UNSUPPORTED_OPERATION'
+                    })
+                }).toThrow('Not an instance of StreamrClientError:\nReceived: "mock-error')
+            })
+
+            it('inverse', () => {
+                const actual = new StreamrClientError('Foobar', 'UNKNOWN_ERROR')
+                expect(() => {
+                    expect(() => { throw actual }).not.toThrowStreamrError(actual)
+                }).toThrow('Expected not to throw StreamrClientError')
+            })
+        })
+    })
+})