diff --git a/compiler/build.gradle b/compiler/build.gradle
index 228d18773..bc08e979d 100644
--- a/compiler/build.gradle
+++ b/compiler/build.gradle
@@ -23,6 +23,7 @@ dependencies {
     implementation 'org.jetbrains.kotlinx:kotlinx-cli:0.3.3'
     implementation "com.michael-bull.kotlin-result:kotlin-result-jvm:1.1.12"
 
+    testImplementation 'io.kotest:kotest-runner-junit5-jvm:4.6.3'
     testImplementation "org.jetbrains.kotlin:kotlin-test-junit5"
     testImplementation 'org.junit.jupiter:junit-jupiter-api:5.7.2'
     testImplementation 'org.hamcrest:hamcrest:2.2'
diff --git a/compiler/compiler.iml b/compiler/compiler.iml
index 0a11b9cb7..2066e7a02 100644
--- a/compiler/compiler.iml
+++ b/compiler/compiler.iml
@@ -25,5 +25,8 @@
     <orderEntry type="module" module-name="codeOptimizers" />
     <orderEntry type="module" module-name="compilerInterfaces" />
     <orderEntry type="module" module-name="codeGeneration" />
+    <orderEntry type="library" name="io.kotest.assertions.core.jvm" level="project" />
+    <orderEntry type="library" name="io.kotest.property.jvm" level="project" />
+    <orderEntry type="library" name="io.kotest.runner.junit5.jvm" level="project" />
   </component>
 </module>
\ No newline at end of file
diff --git a/compilerAst/build.gradle b/compilerAst/build.gradle
index 851af1f91..8990a513d 100644
--- a/compilerAst/build.gradle
+++ b/compilerAst/build.gradle
@@ -16,8 +16,6 @@ dependencies {
     implementation project(':parser')
 
     testImplementation 'io.kotest:kotest-runner-junit5-jvm:4.6.3'
-    testImplementation "org.jetbrains.kotlin:kotlin-test-junit5"
-    testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.7.2'
 }
 
 configurations.all {
diff --git a/compilerAst/compilerAst.iml b/compilerAst/compilerAst.iml
index 6d79055c8..3d3c487dc 100644
--- a/compilerAst/compilerAst.iml
+++ b/compilerAst/compilerAst.iml
@@ -14,7 +14,8 @@
     <orderEntry type="module" module-name="parser" />
     <orderEntry type="library" name="antlr.antlr4" level="project" />
     <orderEntry type="library" name="michael.bull.kotlin.result.jvm" level="project" />
-    <orderEntry type="library" name="io.kotest.runner.junit5.jvm" level="project" />
     <orderEntry type="library" name="io.kotest.assertions.core.jvm" level="project" />
+    <orderEntry type="library" name="io.kotest.property.jvm" level="project" />
+    <orderEntry type="library" name="io.kotest.runner.junit5.jvm" level="project" />
   </component>
 </module>
\ No newline at end of file
diff --git a/compilerAst/test/TestProg8Parser.kt b/compilerAst/test/TestProg8Parser.kt
index fbd0afe8c..8816b4f0e 100644
--- a/compilerAst/test/TestProg8Parser.kt
+++ b/compilerAst/test/TestProg8Parser.kt
@@ -1,6 +1,13 @@
 package prog8tests.ast
 
+import io.kotest.assertions.throwables.shouldThrow
+import io.kotest.assertions.withClue
 import io.kotest.core.spec.style.FunSpec
+import io.kotest.matchers.shouldBe
+import io.kotest.matchers.shouldNotBe
+import io.kotest.matchers.string.shouldContain
+import io.kotest.matchers.string.shouldStartWith
+import io.kotest.matchers.types.instanceOf
 import prog8.ast.IFunctionCall
 import prog8.ast.Module
 import prog8.ast.Node
@@ -22,7 +29,6 @@ import kotlin.io.path.Path
 import kotlin.io.path.isRegularFile
 import kotlin.io.path.name
 import kotlin.io.path.nameWithoutExtension
-import kotlin.test.*
 
 
 class TestProg8Parser: FunSpec( {
@@ -34,14 +40,14 @@ class TestProg8Parser: FunSpec( {
 
             // #40: Prog8ANTLRParser would report (throw) "missing <EOL> at '<EOF>'"
             val module = parseModule(src)
-            assertEquals(1, module.statements.size)
+            module.statements.size shouldBe 1
         }
 
         test("is still accepted - #40, fixed by #45") {
             val nl = "\n" // say, Unix-style (different flavours tested elsewhere)
             val srcText = "foo {" + nl + "}" + nl  // source does end with a newline (issue #40)
             val module = parseModule(SourceCode.Text(srcText))
-            assertEquals(1, module.statements.size)
+            module.statements.size shouldBe 1
         }
     }
 
@@ -55,21 +61,21 @@ class TestProg8Parser: FunSpec( {
             // GOOD: 2nd block `bar` does start on a new line; however, a nl at the very end ain't needed
             val srcGood = "foo {" + nl + "}" + nl + "bar {" + nl + "}"
 
-            assertFailsWith<ParseError> { parseModule(SourceCode.Text(srcBad)) }
+            shouldThrow<ParseError> { parseModule(SourceCode.Text(srcBad)) }
             val module = parseModule(SourceCode.Text(srcGood))
-            assertEquals(2, module.statements.size)
+            module.statements.size shouldBe 2
         }
 
         test("is required between two Blocks or Directives - #47") {
             // block and block
-            assertFailsWith<ParseError>{ parseModule(SourceCode.Text("""
+            shouldThrow<ParseError>{ parseModule(SourceCode.Text("""
                 blockA {
                 } blockB {            
                 }            
             """)) }
 
             // block and directive
-            assertFailsWith<ParseError>{ parseModule(SourceCode.Text("""
+            shouldThrow<ParseError>{ parseModule(SourceCode.Text("""
                 blockB {            
                 } %import textio            
             """)) }
@@ -78,12 +84,12 @@ class TestProg8Parser: FunSpec( {
             // Leaving them in anyways.
 
             // dir and block
-            assertFailsWith<ParseError>{ parseModule(SourceCode.Text("""
+            shouldThrow<ParseError>{ parseModule(SourceCode.Text("""
                 %import textio blockB {            
                 }            
             """)) }
 
-            assertFailsWith<ParseError>{ parseModule(SourceCode.Text("""
+            shouldThrow<ParseError>{ parseModule(SourceCode.Text("""
                 %import textio %import syslib            
             """)) }
         }
@@ -112,7 +118,7 @@ class TestProg8Parser: FunSpec( {
                 nlUnix      // end with newline (see testModuleSourceNeedNotEndWithNewline)
 
             val module = parseModule(SourceCode.Text(srcText))
-            assertEquals(2, module.statements.size)
+            module.statements.size shouldBe 2
         }
     }
 
@@ -129,7 +135,7 @@ class TestProg8Parser: FunSpec( {
                 }
             """
             val module = parseModule(SourceCode.Text(srcText))
-            assertEquals(1, module.statements.size)
+            module.statements.size shouldBe 1
         }
 
         test("are ok between blocks - #47") {
@@ -145,7 +151,7 @@ class TestProg8Parser: FunSpec( {
                 }
             """
             val module = parseModule(SourceCode.Text(srcText))
-            assertEquals(2, module.statements.size)
+            module.statements.size shouldBe 2
         }
 
         test("are ok after last block - #47") {
@@ -159,7 +165,7 @@ class TestProg8Parser: FunSpec( {
                 
             """
             val module = parseModule(SourceCode.Text(srcText))
-            assertEquals(1, module.statements.size)
+            module.statements.size shouldBe 1
         }
     }
 
@@ -170,20 +176,20 @@ class TestProg8Parser: FunSpec( {
             val text = "%import ${importedNoExt.name}"
             val module = parseModule(SourceCode.Text(text))
 
-            assertEquals(1, module.statements.size)
+            module.statements.size shouldBe 1
         }
     }
 
     context("EmptySourcecode") {
         test("from an empty string should result in empty Module") {
             val module = parseModule(SourceCode.Text(""))
-            assertEquals(0, module.statements.size)
+            module.statements.size shouldBe 0
         }
 
         test("from an empty file should result in empty Module") {
             val path = assumeReadableFile(fixturesDir, "empty.p8")
             val module = parseModule(SourceCode.File(path))
-            assertEquals(0, module.statements.size)
+            module.statements.size shouldBe 0
         }
     }
 
@@ -196,13 +202,13 @@ class TestProg8Parser: FunSpec( {
             val module = parseModule(SourceCode.Text(srcText))
 
             // Note: assertContains has *actual* as first param
-            assertContains(module.name, Regex("^<String@[0-9a-f\\-]+>$"))
+            module.name shouldContain Regex("^<String@[0-9a-f\\-]+>$")
         }
 
         test("parsed from a file") {
             val path = assumeReadableFile(fixturesDir, "simple_main.p8")
             val module = parseModule(SourceCode.File(path))
-            assertEquals(path.nameWithoutExtension, module.name)
+            module.name shouldBe path.nameWithoutExtension
         }
     }
 
@@ -216,10 +222,10 @@ class TestProg8Parser: FunSpec( {
             expEndCol: Int? = null
         ) {
             require(!listOf(expLine, expStartCol, expEndCol).all { it == null })
-            if (expLine != null) assertEquals(expLine, actual.line, ".position.line (1-based)")
-            if (expStartCol != null) assertEquals(expStartCol, actual.startCol, ".position.startCol (0-based)")
-            if (expEndCol != null) assertEquals(expEndCol, actual.endCol, ".position.endCol (0-based)")
-            if (expFile != null) assertEquals(expFile, actual.file, ".position.file")
+            if (expLine != null) actual.line shouldBe expLine
+            if (expStartCol != null) actual.startCol shouldBe expStartCol
+            if (expEndCol != null) actual.endCol shouldBe expEndCol
+            if (expFile != null) actual.file shouldBe expFile
         }
 
         fun assertPosition(
@@ -230,11 +236,10 @@ class TestProg8Parser: FunSpec( {
             expEndCol: Int? = null
         ) {
             require(!listOf(expLine, expStartCol, expEndCol).all { it == null })
-            if (expLine != null) assertEquals(expLine, actual.line, ".position.line (1-based)")
-            if (expStartCol != null) assertEquals(expStartCol, actual.startCol, ".position.startCol (0-based)")
-            if (expEndCol != null) assertEquals(expEndCol, actual.endCol, ".position.endCol (0-based)")
-            // Note: assertContains expects *actual* value first
-            if (expFile != null) assertContains(actual.file, expFile, ".position.file")
+            if (expLine != null) actual.line shouldBe expLine
+            if (expStartCol != null) actual.startCol shouldBe expStartCol
+            if (expEndCol != null) actual.endCol shouldBe expEndCol
+            if (expFile != null) actual.file shouldContain expFile
         }
 
         fun assertPositionOf(
@@ -259,14 +264,14 @@ class TestProg8Parser: FunSpec( {
         test("in ParseError from bad string source code") {
             val srcText = "bad * { }\n"
 
-            val e = assertFailsWith<ParseError> { parseModule(SourceCode.Text(srcText)) }
+            val e = shouldThrow<ParseError> { parseModule(SourceCode.Text(srcText)) }
             assertPosition(e.position, Regex("^<String@[0-9a-f\\-]+>$"), 1, 4, 4)
         }
 
         test("in ParseError from bad file source code") {
             val path = assumeReadableFile(fixturesDir, "file_with_syntax_error.p8")
 
-            val e = assertFailsWith<ParseError> { parseModule(SourceCode.File(path)) }
+            val e = shouldThrow<ParseError> { parseModule(SourceCode.File(path)) }
             assertPosition(e.position, SourceCode.relative(path).toString(), 2, 6)
         }
 
@@ -353,8 +358,8 @@ class TestProg8Parser: FunSpec( {
             val path = assumeReadableFile(fixturesDir, "simple_main.p8")
             val module = parseModule(SourceCode.File(path))
             assertSomethingForAllNodes(module) {
-                assertFalse(Path(it.position.file).isAbsolute)
-                assertTrue(Path(it.position.file).isRegularFile())
+                Path(it.position.file).isAbsolute shouldBe false
+                Path(it.position.file).isRegularFile() shouldBe true
             }
         }
 
@@ -371,7 +376,7 @@ class TestProg8Parser: FunSpec( {
             """.trimIndent()
             val module = parseModule(SourceCode.Text(srcText))
             assertSomethingForAllNodes(module) {
-                assertTrue(it.position.file.startsWith(SourceCode.stringSourcePrefix))
+                it.position.file shouldStartWith SourceCode.stringSourcePrefix
             }
         }
 
@@ -380,7 +385,7 @@ class TestProg8Parser: FunSpec( {
             val resource = SourceCode.Resource("prog8lib/math.p8")
             val module = parseModule(resource)
             assertSomethingForAllNodes(module) {
-                assertTrue(it.position.file.startsWith(SourceCode.libraryFilePrefix))
+                it.position.file shouldStartWith SourceCode.libraryFilePrefix
             }
         }
     }
@@ -402,9 +407,9 @@ class TestProg8Parser: FunSpec( {
                 .statements.filterIsInstance<Subroutine>()[0]
             val funCall = startSub.statements.filterIsInstance<IFunctionCall>().first()
 
-            assertIs<CharLiteral>(funCall.args[0])
+            funCall.args[0] shouldBe(instanceOf<CharLiteral>())
             val char = funCall.args[0] as CharLiteral
-            assertEquals('\n', char.value)
+            char.value shouldBe '\n'
         }
 
         test("on rhs of block-level var decl, no AltEnc") {
@@ -419,8 +424,8 @@ class TestProg8Parser: FunSpec( {
                 .statements.filterIsInstance<VarDecl>()[0]
 
             val rhs = decl.value as CharLiteral
-            assertEquals('x', rhs.value, "char literal's .value")
-            assertEquals(false, rhs.altEncoding, "char literal's .altEncoding")
+            rhs.value shouldBe 'x'
+            rhs.altEncoding shouldBe false
         }
 
         test("on rhs of block-level const decl, with AltEnc") {
@@ -435,8 +440,8 @@ class TestProg8Parser: FunSpec( {
                 .statements.filterIsInstance<VarDecl>()[0]
 
             val rhs = decl.value as CharLiteral
-            assertEquals('x', rhs.value, "char literal's .value")
-            assertEquals(true, rhs.altEncoding, "char literal's .altEncoding")
+            rhs.value shouldBe 'x'
+            rhs.altEncoding shouldBe true
         }
 
         test("on rhs of subroutine-level var decl, no AltEnc") {
@@ -454,8 +459,8 @@ class TestProg8Parser: FunSpec( {
                 .statements.filterIsInstance<VarDecl>()[0]
 
             val rhs = decl.value as CharLiteral
-            assertEquals('x', rhs.value, "char literal's .value")
-            assertEquals(false, rhs.altEncoding, "char literal's .altEncoding")
+            rhs.value shouldBe 'x'
+            rhs.altEncoding shouldBe false
         }
 
         test("on rhs of subroutine-level const decl, with AltEnc") {
@@ -473,8 +478,8 @@ class TestProg8Parser: FunSpec( {
                 .statements.filterIsInstance<VarDecl>()[0]
 
             val rhs = decl.value as CharLiteral
-            assertEquals('x', rhs.value, "char literal's .value")
-            assertEquals(true, rhs.altEncoding, "char literal's .altEncoding")
+            rhs.value shouldBe 'x'
+            rhs.altEncoding shouldBe true
         }
     }
 
@@ -504,26 +509,26 @@ class TestProg8Parser: FunSpec( {
                 .statements.filterIsInstance<ForLoop>()
                 .map { it.iterable }
 
-            assertEquals(5, iterables.size)
+            iterables.size shouldBe 5
 
             val it0 = iterables[0] as RangeExpr
-            assertIs<StringLiteralValue>(it0.from, "parser should leave it as is")
-            assertIs<StringLiteralValue>(it0.to, "parser should leave it as is")
+            it0.from shouldBe instanceOf<StringLiteralValue>()
+            it0.to shouldBe instanceOf<StringLiteralValue>()
 
             val it1 = iterables[1] as StringLiteralValue
-            assertEquals("something", it1.value, "parser should leave it as is")
+            it1.value shouldBe "something"
 
             val it2 = iterables[2] as RangeExpr
-            assertIs<CharLiteral>(it2.from, "parser should leave it as is")
-            assertIs<CharLiteral>(it2.to, "parser should leave it as is")
+            it2.from shouldBe instanceOf<CharLiteral>()
+            it2.to shouldBe instanceOf<CharLiteral>()
 
             val it3 = iterables[3] as RangeExpr
-            assertIs<NumericLiteralValue>(it3.from, "parser should leave it as is")
-            assertIs<NumericLiteralValue>(it3.to, "parser should leave it as is")
+            it3.from shouldBe instanceOf<NumericLiteralValue>()
+            it3.to shouldBe instanceOf<NumericLiteralValue>()
 
             val it4 = iterables[4] as RangeExpr
-            assertIs<NumericLiteralValue>(it4.from, "parser should leave it as is")
-            assertIs<NumericLiteralValue>(it4.to, "parser should leave it as is")
+            it4.from shouldBe instanceOf<NumericLiteralValue>()
+            it4.to shouldBe instanceOf<NumericLiteralValue>()
         }
     }
 
@@ -532,33 +537,33 @@ class TestProg8Parser: FunSpec( {
         val char2 = CharLiteral('z', true, Position.DUMMY)
 
         val program = Program("test", DummyFunctions, DummyMemsizer, AsciiStringEncoder)
-        assertEquals(65, char1.constValue(program).number.toInt())
-        assertEquals(122, char2.constValue(program).number.toInt())
+        char1.constValue(program).number.toInt() shouldBe 65
+        char2.constValue(program).number.toInt() shouldBe 122
     }
 
     test("testLiteralValueComparisons") {
         val ten = NumericLiteralValue(DataType.UWORD, 10, Position.DUMMY)
         val nine = NumericLiteralValue(DataType.UBYTE, 9, Position.DUMMY)
-        assertEquals(ten, ten)
-        assertNotEquals(ten, nine)
-        assertFalse(ten != ten)
-        assertTrue(ten != nine)
+        ten shouldBe ten
+        nine shouldNotBe ten
+        (ten != ten) shouldBe false
+        (ten != nine) shouldBe true
 
-        assertTrue(ten > nine)
-        assertTrue(ten >= nine)
-        assertTrue(ten >= ten)
-        assertFalse(ten > ten)
+        (ten > nine) shouldBe true
+        (ten >= nine) shouldBe true
+        (ten >= ten) shouldBe true
+        (ten > ten) shouldBe false
 
-        assertFalse(ten < nine)
-        assertFalse(ten <= nine)
-        assertTrue(ten <= ten)
-        assertFalse(ten < ten)
+        (ten < nine) shouldBe false
+        (ten <= nine) shouldBe false
+        (ten <= ten) shouldBe true
+        (ten < ten) shouldBe false
 
         val abc = StringLiteralValue("abc", false, Position.DUMMY)
         val abd = StringLiteralValue("abd", false, Position.DUMMY)
-        assertEquals(abc, abc)
-        assertTrue(abc!=abd)
-        assertFalse(abc!=abc)
+        abc shouldBe abc
+        (abc!=abd) shouldBe true
+        (abc!=abc) shouldBe false
     }
 
     test("testAnonScopeStillContainsVarsDirectlyAfterParse") {
@@ -576,12 +581,18 @@ class TestProg8Parser: FunSpec( {
         val mainBlock = module.statements.single() as Block
         val start = mainBlock.statements.single() as Subroutine
         val repeatbody = (start.statements.single() as RepeatLoop).body
-        assertFalse(mainBlock.statements.any { it is VarDecl }, "no vars moved to main block")
-        assertFalse(start.statements.any { it is VarDecl }, "no vars moved to start sub")
-        assertTrue(repeatbody.statements[0] is VarDecl, "var is still in repeat block (anonymousscope)")
+        withClue("no vars moved to main block") {
+            mainBlock.statements.any { it is VarDecl } shouldBe false
+        }
+        withClue("no vars moved to start sub") {
+            start.statements.any { it is VarDecl } shouldBe false
+        }
+        withClue("\"var is still in repeat block (anonymousscope") {
+            repeatbody.statements[0] shouldBe instanceOf<VarDecl>()
+        }
         val initvalue = (repeatbody.statements[0] as VarDecl).value as? NumericLiteralValue
-        assertEquals(99, initvalue?.number?.toInt())
-        assertTrue(repeatbody.statements[1] is PostIncrDecr)
+        initvalue?.number?.toInt() shouldBe 99
+        repeatbody.statements[1] shouldBe instanceOf<PostIncrDecr>()
         // the ast processing steps used in the compiler, will eventually move the var up to the containing scope (subroutine).
     }
 
@@ -612,6 +623,6 @@ class TestProg8Parser: FunSpec( {
         val mainBlock = module.statements.single() as Block
         val start = mainBlock.statements.single() as Subroutine
         val labels = start.statements.filterIsInstance<Label>()
-        assertEquals(1, labels.size, "only one label in subroutine scope")
+        labels.size shouldBe 1
     }
 })
diff --git a/compilerAst/test/TestSourceCode.kt b/compilerAst/test/TestSourceCode.kt
index db2c8b3bb..0035582ee 100644
--- a/compilerAst/test/TestSourceCode.kt
+++ b/compilerAst/test/TestSourceCode.kt
@@ -1,6 +1,9 @@
 package prog8tests.ast
 
+import io.kotest.assertions.throwables.shouldThrow
 import io.kotest.core.spec.style.AnnotationSpec
+import io.kotest.matchers.shouldBe
+import io.kotest.matchers.string.shouldContain
 import prog8.parser.SourceCode
 import prog8.parser.SourceCode.Companion.libraryFilePrefix
 import prog8tests.ast.helpers.assumeNotExists
@@ -8,7 +11,6 @@ import prog8tests.ast.helpers.assumeReadableFile
 import prog8tests.ast.helpers.fixturesDir
 import prog8tests.ast.helpers.resourcesDir
 import kotlin.io.path.Path
-import kotlin.test.*
 
 
 class TestSourceCode: AnnotationSpec() {
@@ -21,30 +23,30 @@ class TestSourceCode: AnnotationSpec() {
         val src = SourceCode.Text(text)
         val actualText = src.getCharStream().toString()
 
-        assertContains(src.origin, Regex("^<String@[0-9a-f\\-]+>$"))
-        assertEquals(text, actualText)
-        assertFalse(src.isFromResources)
-        assertFalse(src.isFromFilesystem)
-        assertTrue(src.toString().startsWith("prog8.parser.SourceCode"))
+        src.origin shouldContain Regex("^<String@[0-9a-f\\-]+>$")
+        actualText shouldBe text
+        src.isFromResources shouldBe false
+        src.isFromFilesystem shouldBe false
+        src.toString().startsWith("prog8.parser.SourceCode") shouldBe true
     }
 
     @Test
     fun testFromPathWithNonExistingPath() {
         val filename = "i_do_not_exist.p8"
         val path = assumeNotExists(fixturesDir, filename)
-        assertFailsWith<NoSuchFileException> { SourceCode.File(path) }
+        shouldThrow<NoSuchFileException> { SourceCode.File(path) }
     }
 
     @Test
     fun testFromPathWithMissingExtension_p8() {
         val pathWithoutExt = assumeNotExists(fixturesDir,"simple_main")
         assumeReadableFile(fixturesDir,"simple_main.p8")
-        assertFailsWith<NoSuchFileException> { SourceCode.File(pathWithoutExt) }
+        shouldThrow<NoSuchFileException> { SourceCode.File(pathWithoutExt) }
     }
 
     @Test
     fun testFromPathWithDirectory() {
-        assertFailsWith<AccessDeniedException> { SourceCode.File(fixturesDir) }
+        shouldThrow<AccessDeniedException> { SourceCode.File(fixturesDir) }
     }
 
     @Test
@@ -53,10 +55,10 @@ class TestSourceCode: AnnotationSpec() {
         val path = assumeReadableFile(fixturesDir, filename)
         val src = SourceCode.File(path)
         val expectedOrigin = SourceCode.relative(path).toString()
-        assertEquals(expectedOrigin, src.origin)
-        assertEquals(path.toFile().readText(), src.readText())
-        assertFalse(src.isFromResources)
-        assertTrue(src.isFromFilesystem)
+        src.origin shouldBe expectedOrigin
+        src.readText() shouldBe path.toFile().readText()
+        src.isFromResources shouldBe false
+        src.isFromFilesystem shouldBe true
     }
 
     @Test
@@ -66,8 +68,8 @@ class TestSourceCode: AnnotationSpec() {
         val srcFile = assumeReadableFile(path).toFile()
         val src = SourceCode.File(path)
         val expectedOrigin = SourceCode.relative(path).toString()
-        assertEquals(expectedOrigin, src.origin)
-        assertEquals(srcFile.readText(), src.readText())
+        src.origin shouldBe expectedOrigin
+        src.readText() shouldBe srcFile.readText()
     }
 
     @Test
@@ -76,10 +78,10 @@ class TestSourceCode: AnnotationSpec() {
         val srcFile = assumeReadableFile(resourcesDir, pathString).toFile()
         val src = SourceCode.Resource(pathString)
 
-        assertEquals("$libraryFilePrefix/$pathString", src.origin)
-        assertEquals(srcFile.readText(), src.readText())
-        assertTrue(src.isFromResources)
-        assertFalse(src.isFromFilesystem)
+        src.origin shouldBe "$libraryFilePrefix/$pathString"
+        src.readText() shouldBe srcFile.readText()
+        src.isFromResources shouldBe true
+        src.isFromFilesystem shouldBe false
     }
 
     @Test
@@ -88,8 +90,8 @@ class TestSourceCode: AnnotationSpec() {
         val srcFile = assumeReadableFile(resourcesDir, pathString.substring(1)).toFile()
         val src = SourceCode.Resource(pathString)
 
-        assertEquals("$libraryFilePrefix$pathString", src.origin)
-        assertEquals(srcFile.readText(), src.readText())
+        src.origin shouldBe "$libraryFilePrefix$pathString"
+        src.readText() shouldBe srcFile.readText()
     }
 
     @Test
@@ -98,9 +100,9 @@ class TestSourceCode: AnnotationSpec() {
         val srcFile = assumeReadableFile(resourcesDir, pathString).toFile()
         val src = SourceCode.Resource(pathString)
 
-        assertEquals("$libraryFilePrefix/$pathString", src.origin)
-        assertEquals(srcFile.readText(), src.readText())
-        assertTrue(src.isFromResources, ".isFromResources")
+        src.origin shouldBe "$libraryFilePrefix/$pathString"
+        src.readText() shouldBe srcFile.readText()
+        src.isFromResources shouldBe true
     }
 
     @Test
@@ -109,8 +111,8 @@ class TestSourceCode: AnnotationSpec() {
         val srcFile = assumeReadableFile(resourcesDir, pathString.substring(1)).toFile()
         val src = SourceCode.Resource(pathString)
 
-        assertEquals("$libraryFilePrefix$pathString", src.origin)
-        assertEquals(srcFile.readText(), src.readText())
+        src.origin shouldBe "$libraryFilePrefix$pathString"
+        src.readText() shouldBe srcFile.readText()
     }
 
     @Test
@@ -119,9 +121,9 @@ class TestSourceCode: AnnotationSpec() {
         val srcFile = assumeReadableFile(resourcesDir, pathString.substring(1)).toFile()
         val src = SourceCode.Resource(pathString)
 
-        assertEquals("$libraryFilePrefix/prog8lib/math.p8", src.origin)
-        assertEquals(srcFile.readText(), src.readText())
-        assertTrue(src.isFromResources, ".isFromResources")
+        src.origin shouldBe "$libraryFilePrefix/prog8lib/math.p8"
+        src.readText() shouldBe srcFile.readText()
+        src.isFromResources shouldBe true
     }
 
 
@@ -130,13 +132,13 @@ class TestSourceCode: AnnotationSpec() {
         val pathString = "/prog8lib/i_do_not_exist"
         assumeNotExists(resourcesDir, pathString.substring(1))
 
-        assertFailsWith<NoSuchFileException> { SourceCode.Resource(pathString) }
+        shouldThrow<NoSuchFileException> { SourceCode.Resource(pathString) }
     }
     @Test
     fun testFromResourcesWithNonExistingFile_withoutLeadingSlash() {
         val pathString = "prog8lib/i_do_not_exist"
         assumeNotExists(resourcesDir, pathString)
 
-        assertFailsWith<NoSuchFileException> { SourceCode.Resource(pathString) }
+        shouldThrow<NoSuchFileException> { SourceCode.Resource(pathString) }
     }
 }
diff --git a/compilerAst/test/TestSubroutines.kt b/compilerAst/test/TestSubroutines.kt
index f26d752cb..2356e1163 100644
--- a/compilerAst/test/TestSubroutines.kt
+++ b/compilerAst/test/TestSubroutines.kt
@@ -1,14 +1,12 @@
 package prog8tests.ast
 
 import io.kotest.core.spec.style.AnnotationSpec
+import io.kotest.matchers.shouldBe
 import prog8.ast.base.DataType
 import prog8.ast.statements.Block
 import prog8.ast.statements.Subroutine
 import prog8.parser.Prog8Parser.parseModule
 import prog8.parser.SourceCode
-import kotlin.test.assertEquals
-import kotlin.test.assertFalse
-import kotlin.test.assertTrue
 
 
 class TestSubroutines: AnnotationSpec() {
@@ -31,12 +29,12 @@ class TestSubroutines: AnnotationSpec() {
         val mainBlock = module.statements.single() as Block
         val asmfunc = mainBlock.statements.filterIsInstance<Subroutine>().single { it.name=="asmfunc"}
         val func = mainBlock.statements.filterIsInstance<Subroutine>().single { it.name=="func"}
-        assertTrue(asmfunc.isAsmSubroutine)
-        assertEquals(DataType.STR, asmfunc.parameters.single().type)
-        assertTrue(asmfunc.statements.isEmpty())
-        assertFalse(func.isAsmSubroutine)
-        assertEquals(DataType.STR, func.parameters.single().type)
-        assertTrue(func.statements.isEmpty())
+        asmfunc.isAsmSubroutine shouldBe true
+        asmfunc.parameters.single().type shouldBe DataType.STR
+        asmfunc.statements.isEmpty() shouldBe true
+        func.isAsmSubroutine shouldBe false
+        func.parameters.single().type shouldBe DataType.STR
+        func.statements.isEmpty() shouldBe true
     }
 
     @Test
@@ -57,11 +55,11 @@ class TestSubroutines: AnnotationSpec() {
         val mainBlock = module.statements.single() as Block
         val asmfunc = mainBlock.statements.filterIsInstance<Subroutine>().single { it.name=="asmfunc"}
         val func = mainBlock.statements.filterIsInstance<Subroutine>().single { it.name=="func"}
-        assertTrue(asmfunc.isAsmSubroutine)
-        assertEquals(DataType.ARRAY_UB, asmfunc.parameters.single().type)
-        assertTrue(asmfunc.statements.isEmpty())
-        assertFalse(func.isAsmSubroutine)
-        assertEquals(DataType.ARRAY_UB, func.parameters.single().type)
-        assertTrue(func.statements.isEmpty())
+        asmfunc.isAsmSubroutine shouldBe true
+        asmfunc.parameters.single().type shouldBe DataType.ARRAY_UB
+        asmfunc.statements.isEmpty() shouldBe true
+        func.isAsmSubroutine shouldBe false
+        func.parameters.single().type shouldBe DataType.ARRAY_UB
+        func.statements.isEmpty() shouldBe true
     }
 }
diff --git a/compilerAst/test/helpers/paths.kt b/compilerAst/test/helpers/paths.kt
index 30a753448..07fd55cf3 100644
--- a/compilerAst/test/helpers/paths.kt
+++ b/compilerAst/test/helpers/paths.kt
@@ -1,10 +1,10 @@
 package prog8tests.ast.helpers
 
+import io.kotest.assertions.withClue
+import io.kotest.matchers.shouldBe
 import java.nio.file.Files
 import java.nio.file.Path
 import kotlin.io.path.*
-import kotlin.test.assertFalse
-import kotlin.test.assertTrue
 
 
 val workingDir = assumeDirectory("").absolute()   // Note: "." does NOT work..!
@@ -20,7 +20,9 @@ fun createIfNotExists(workingDir: Path, path: String): Path {
 }
 
 fun assumeNotExists(path: Path): Path {
-    assertFalse(path.exists(), "sanity check: should not exist: ${path.absolute()}")
+    withClue("sanity check: should not exist: ${path.absolute()}") {
+        path.exists() shouldBe false
+    }
     return path
 }
 
@@ -28,12 +30,16 @@ fun assumeNotExists(pathStr: String): Path = assumeNotExists(Path(pathStr))
 fun assumeNotExists(path: Path, other: String): Path = assumeNotExists(path / other)
 
 fun assumeReadable(path: Path): Path {
-    assertTrue(path.isReadable(), "sanity check: should be readable: ${path.absolute()}")
+    withClue("sanity check: should be readable: ${path.absolute()}") {
+        path.isReadable() shouldBe true
+    }
     return path
 }
 
 fun assumeReadableFile(path: Path): Path {
-    assertTrue(path.isRegularFile(), "sanity check: should be normal file: ${path.absolute()}")
+    withClue("sanity check: should be normal file: ${path.absolute()}") {
+        path.isRegularFile() shouldBe true
+    }
     return assumeReadable(path)
 }
 
@@ -44,7 +50,9 @@ fun assumeReadableFile(path: Path, other: String): Path = assumeReadableFile(pat
 fun assumeReadableFile(path: Path, other: Path): Path = assumeReadableFile(path / other)
 
 fun assumeDirectory(path: Path): Path {
-    assertTrue(path.isDirectory(), "sanity check; should be directory: $path")
+    withClue("sanity check; should be directory: $path") {
+        path.isDirectory() shouldBe true
+    }
     return path
 }
 
diff --git a/compilerAst/test/helpers_pathsTests.kt b/compilerAst/test/helpers_pathsTests.kt
index 90afed965..ca586dd53 100644
--- a/compilerAst/test/helpers_pathsTests.kt
+++ b/compilerAst/test/helpers_pathsTests.kt
@@ -1,12 +1,12 @@
 package prog8tests.ast
 
+import io.kotest.assertions.throwables.shouldThrow
 import io.kotest.assertions.withClue
 import io.kotest.core.spec.style.FunSpec
+import io.kotest.matchers.shouldBe
 import prog8tests.ast.helpers.*
 import kotlin.io.path.Path
 import kotlin.io.path.div
-import kotlin.test.assertEquals
-import kotlin.test.assertFailsWith
 
 
 // Do not move into folder helpers/!
@@ -22,18 +22,18 @@ class PathsHelpersTests: FunSpec({
             test("on non-existing path") {
                 val path = fixturesDir / "i_do_not_exist"
                 withClue("should return the path") {
-                    assertEquals(path, assumeNotExists(path))
+                    assumeNotExists(path) shouldBe path
                 }
             }
 
             test("on existing file") {
-                assertFailsWith<java.lang.AssertionError> {
+                shouldThrow<java.lang.AssertionError> {
                     assumeNotExists(fixturesDir / "simple_main.p8")
                 }
             }
 
             test("on existing directory") {
-                assertFailsWith<java.lang.AssertionError> {
+                shouldThrow<java.lang.AssertionError> {
                     assumeNotExists(fixturesDir)
                 }
             }
@@ -44,19 +44,19 @@ class PathsHelpersTests: FunSpec({
             test("on non-existing path") {
                 val path = fixturesDir / "i_do_not_exist"
                 withClue("should return the path") {
-                    assertEquals(path, assumeNotExists("$path"))
+                    assumeNotExists("$path") shouldBe path
                 }
             }
 
             test("on existing file") {
                 val path = fixturesDir / "simple_main.p8"
-                assertFailsWith<java.lang.AssertionError> {
+                shouldThrow<java.lang.AssertionError> {
                     assumeNotExists("$path")
                 }
             }
 
             test("on existing directory") {
-                assertFailsWith<java.lang.AssertionError> {
+                shouldThrow<java.lang.AssertionError> {
                     assumeNotExists("$fixturesDir")
                 }
             }
@@ -67,18 +67,18 @@ class PathsHelpersTests: FunSpec({
             test("on non-existing path") {
                 val path = fixturesDir / "i_do_not_exist"
                 withClue("should return the path") {
-                    assertEquals(path, assumeNotExists(fixturesDir, "i_do_not_exist"))
+                    assumeNotExists(fixturesDir / "i_do_not_exist") shouldBe path
                 }
             }
 
             test("on existing file") {
-                assertFailsWith<java.lang.AssertionError> {
+                shouldThrow<java.lang.AssertionError> {
                     assumeNotExists(fixturesDir, "simple_main.p8")
                 }
             }
 
             test("on existing directory") {
-                assertFailsWith<java.lang.AssertionError> {
+                shouldThrow<java.lang.AssertionError> {
                     assumeNotExists(fixturesDir, "..")
                 }
             }
@@ -90,14 +90,14 @@ class PathsHelpersTests: FunSpec({
         context("WithOnePathArg") {
             test("on non-existing path") {
                 val path = fixturesDir / "i_do_not_exist"
-                assertFailsWith<AssertionError> {
+                shouldThrow<AssertionError> {
                     assumeDirectory(path)
                 }
             }
 
             test("on existing file") {
                 val path = fixturesDir / "simple_main.p8"
-                assertFailsWith<AssertionError> {
+                shouldThrow<AssertionError> {
                     assumeDirectory(path)
                 }
             }
@@ -105,7 +105,7 @@ class PathsHelpersTests: FunSpec({
             test("on existing directory") {
                 val path = workingDir
                 withClue("should return the path") {
-                    assertEquals(path, assumeDirectory(path))
+                    assumeDirectory(path) shouldBe path
                 }
             }
         }
@@ -113,14 +113,14 @@ class PathsHelpersTests: FunSpec({
         context("WithOneStringArg") {
             test("on non-existing path") {
                 val path = fixturesDir / "i_do_not_exist"
-                assertFailsWith<AssertionError> {
+                shouldThrow<AssertionError> {
                     assumeDirectory("$path")
                 }
             }
 
             test("on existing file") {
                 val path = fixturesDir / "simple_main.p8"
-                assertFailsWith<AssertionError> {
+                shouldThrow<AssertionError> {
                     assumeDirectory("$path")
                 }
             }
@@ -128,20 +128,20 @@ class PathsHelpersTests: FunSpec({
             test("on existing directory") {
                 val path = workingDir
                 withClue("should return the path") {
-                    assertEquals(path, assumeDirectory("$path"))
+                    assumeDirectory("$path") shouldBe path
                 }
             }
         }
 
         context("WithPathAndStringArgs") {
             test("on non-existing path") {
-                assertFailsWith<AssertionError> {
+                shouldThrow<AssertionError> {
                     assumeDirectory(fixturesDir, "i_do_not_exist")
                 }
             }
 
             test("on existing file") {
-                assertFailsWith<AssertionError> {
+                shouldThrow<AssertionError> {
                     assumeDirectory(fixturesDir, "simple_main.p8")
                 }
             }
@@ -149,20 +149,20 @@ class PathsHelpersTests: FunSpec({
             test("on existing directory") {
                 val path = workingDir / ".."
                 withClue("should return resulting path") {
-                    assertEquals(path, assumeDirectory(workingDir, ".."))
+                    assumeDirectory(workingDir / "..") shouldBe path
                 }
             }
         }
 
         context("WithStringAndStringArgs") {
             test("on non-existing path") {
-                assertFailsWith<AssertionError> {
+                shouldThrow<AssertionError> {
                     assumeDirectory("$fixturesDir", "i_do_not_exist")
                 }
             }
 
             test("on existing file") {
-                assertFailsWith<AssertionError> {
+                shouldThrow<AssertionError> {
                     assumeDirectory("$fixturesDir", "simple_main.p8")
                 }
             }
@@ -170,20 +170,20 @@ class PathsHelpersTests: FunSpec({
             test("on existing directory") {
                 val path = workingDir / ".."
                 withClue("should return resulting path") {
-                    assertEquals(path, assumeDirectory("$workingDir", ".."))
+                    assumeDirectory(workingDir / "..") shouldBe path
                 }
             }
         }
 
         context("WithStringAndPathArgs") {
             test("on non-existing path") {
-                assertFailsWith<AssertionError> {
+                shouldThrow<AssertionError> {
                     assumeDirectory("$fixturesDir", Path("i_do_not_exist"))
                 }
             }
 
             test("on existing file") {
-                assertFailsWith<AssertionError> {
+                shouldThrow<AssertionError> {
                     assumeDirectory("$fixturesDir", Path("simple_main.p8"))
                 }
             }
@@ -191,7 +191,7 @@ class PathsHelpersTests: FunSpec({
             test("on existing directory") {
                 val path = workingDir / ".."
                 withClue("should return resulting path") {
-                    assertEquals(path, assumeDirectory("$workingDir", Path("..")))
+                    assumeDirectory(workingDir / Path("..")) shouldBe path
                 }
             }
         }
@@ -203,7 +203,7 @@ class PathsHelpersTests: FunSpec({
 
             test("on non-existing path") {
                 val path = fixturesDir / "i_do_not_exist"
-                assertFailsWith<AssertionError> {
+                shouldThrow<AssertionError> {
                     assumeReadableFile(path)
                 }
             }
@@ -211,12 +211,12 @@ class PathsHelpersTests: FunSpec({
             test("on readable file") {
                 val path = fixturesDir / "simple_main.p8"
                 withClue("should return the path") {
-                    assertEquals(path, assumeReadableFile(path))
+                    assumeReadableFile(path) shouldBe path
                 }
             }
 
             test("on directory") {
-                assertFailsWith<AssertionError> {
+                shouldThrow<AssertionError> {
                     assumeReadableFile(fixturesDir)
                 }
             }
@@ -226,7 +226,7 @@ class PathsHelpersTests: FunSpec({
 
             test("on non-existing path") {
                 val path = fixturesDir / "i_do_not_exist"
-                assertFailsWith<AssertionError> {
+                shouldThrow<AssertionError> {
                     assumeReadableFile("$path")
                 }
             }
@@ -234,12 +234,12 @@ class PathsHelpersTests: FunSpec({
             test("on readable file") {
                 val path = fixturesDir / "simple_main.p8"
                 withClue("should return the resulting path") {
-                    assertEquals(path, assumeReadableFile("$path"))
+                    assumeReadableFile("$path") shouldBe path
                 }
             }
 
             test("on directory") {
-                assertFailsWith<AssertionError> {
+                shouldThrow<AssertionError> {
                     assumeReadableFile("$fixturesDir")
                 }
             }
@@ -247,7 +247,7 @@ class PathsHelpersTests: FunSpec({
 
         context("WithPathAndStringArgs") {
             test("on non-existing path") {
-                assertFailsWith<java.lang.AssertionError> {
+                shouldThrow<java.lang.AssertionError> {
                     assumeReadableFile(fixturesDir, "i_do_not_exist")
                 }
             }
@@ -255,12 +255,12 @@ class PathsHelpersTests: FunSpec({
             test("on readable file") {
                 val path = fixturesDir / "simple_main.p8"
                 withClue("should return the resulting path") {
-                    assertEquals(path, assumeReadableFile(fixturesDir, "simple_main.p8"))
+                    assumeReadableFile(fixturesDir / "simple_main.p8") shouldBe path
                 }
             }
 
             test("on directory") {
-                assertFailsWith<AssertionError> {
+                shouldThrow<AssertionError> {
                     assumeReadableFile(fixturesDir, "..")
                 }
             }
@@ -268,19 +268,19 @@ class PathsHelpersTests: FunSpec({
 
         context("WithPathAndPathArgs") {
             test("on non-existing path") {
-                assertFailsWith<java.lang.AssertionError> {
+                shouldThrow<java.lang.AssertionError> {
                     assumeReadableFile(fixturesDir, Path("i_do_not_exist"))
                 }
             }
 
             test("on readable file") {
                 withClue("should return the resulting path") {
-                    assertEquals(fixturesDir / "simple_main.p8", assumeReadableFile(fixturesDir, Path("simple_main.p8")))
+                    assumeReadableFile(fixturesDir / Path("simple_main.p8")) shouldBe fixturesDir / "simple_main.p8"
                 }
             }
 
             test("on directory") {
-                assertFailsWith<AssertionError> {
+                shouldThrow<AssertionError> {
                     assumeReadableFile(fixturesDir, Path(".."))
                 }
             }
@@ -288,19 +288,19 @@ class PathsHelpersTests: FunSpec({
 
         context("WithStringAndStringArgs") {
             test("on non-existing path") {
-                assertFailsWith<java.lang.AssertionError> {
+                shouldThrow<java.lang.AssertionError> {
                     assumeReadableFile("$fixturesDir", "i_do_not_exist")
                 }
             }
 
             test("on readable file") {
                 withClue("should return the resulting path") {
-                    assertEquals( fixturesDir / "simple_main.p8", assumeReadableFile(fixturesDir.toString(), "simple_main.p8"))
+                    assumeReadableFile(fixturesDir / "simple_main.p8") shouldBe  fixturesDir / "simple_main.p8"
                 }
             }
 
             test("on directory") {
-                assertFailsWith<AssertionError> {
+                shouldThrow<AssertionError> {
                     assumeReadableFile("$fixturesDir", "..")
                 }
             }
diff --git a/docs/source/todo.rst b/docs/source/todo.rst
index 862d7a33a..91b9ccc64 100644
--- a/docs/source/todo.rst
+++ b/docs/source/todo.rst
@@ -3,8 +3,6 @@ TODO
 
 For next compiler release (7.3)
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-- replace all old asserts in compilerAst tests by kotest equivalents
-- remove kotlin.test and junit dependencies in compilerAst module
 - migrate Compiler tests to KoTest library (this will close github issue #70)
 ...