diff --git a/src/compiler/Compile.go b/src/compiler/Compile.go
index 5dea2cd..eef2adb 100644
--- a/src/compiler/Compile.go
+++ b/src/compiler/Compile.go
@@ -3,12 +3,13 @@ package compiler
 import (
 	"git.urbach.dev/cli/q/src/build"
 	"git.urbach.dev/cli/q/src/errors"
+	"git.urbach.dev/cli/q/src/scanner"
 )
 
 // Compile waits for the scan to finish and compiles all functions.
 func Compile(b *build.Build) (Result, error) {
 	result := Result{}
-	all, err := scan(b)
+	all, err := scanner.Scan(b)
 
 	if err != nil {
 		return result, err
@@ -18,7 +19,6 @@ func Compile(b *build.Build) (Result, error) {
 		return result, errors.NoInputFiles
 	}
 
-	// Resolve the types
 	for _, function := range all.Functions {
 		err := function.ResolveTypes()
 
@@ -27,8 +27,6 @@ func Compile(b *build.Build) (Result, error) {
 		}
 	}
 
-	// Parallel compilation
 	compileFunctions(all.Functions)
-
 	return result, nil
 }
\ No newline at end of file
diff --git a/src/compiler/scan.go b/src/compiler/scan.go
deleted file mode 100644
index 95c2d40..0000000
--- a/src/compiler/scan.go
+++ /dev/null
@@ -1,47 +0,0 @@
-package compiler
-
-import (
-	"git.urbach.dev/cli/q/src/build"
-	"git.urbach.dev/cli/q/src/core"
-	"git.urbach.dev/cli/q/src/fs"
-	"git.urbach.dev/cli/q/src/scanner"
-)
-
-func scan(b *build.Build) (*core.Environment, error) {
-	functions, files, errs := scanner.Scan(b)
-
-	all := &core.Environment{
-		Files:     make([]*fs.File, 0, 8),
-		Functions: make(map[string]*core.Function, 32),
-	}
-
-	for functions != nil || files != nil || errs != nil {
-		select {
-		case f, ok := <-functions:
-			if !ok {
-				functions = nil
-				continue
-			}
-
-			all.Functions[f.String()] = f
-
-		case file, ok := <-files:
-			if !ok {
-				files = nil
-				continue
-			}
-
-			all.Files = append(all.Files, file)
-
-		case err, ok := <-errs:
-			if !ok {
-				errs = nil
-				continue
-			}
-
-			return all, err
-		}
-	}
-
-	return all, nil
-}
\ No newline at end of file
diff --git a/src/errors/Common.go b/src/errors/Common.go
index 71ceb0f..8d72ef2 100644
--- a/src/errors/Common.go
+++ b/src/errors/Common.go
@@ -3,7 +3,7 @@ package errors
 var (
 	ExpectedFunctionDefinition = &String{"Expected function definition"}
 	ExpectedPackageName        = &String{"Expected package name"}
-	InvalidDefinition          = &String{"Invalid definition"}
+	InvalidFunctionDefinition  = &String{"Invalid function definition"}
 	MissingBlockStart          = &String{"Missing '{'"}
 	MissingBlockEnd            = &String{"Missing '}'"}
 	MissingGroupStart          = &String{"Missing '('"}
diff --git a/src/scanner/Scan.go b/src/scanner/Scan.go
index 710dddf..d46798b 100644
--- a/src/scanner/Scan.go
+++ b/src/scanner/Scan.go
@@ -7,7 +7,7 @@ import (
 )
 
 // Scan scans all the files included in the build.
-func Scan(b *build.Build) (<-chan *core.Function, <-chan *fs.File, <-chan error) {
+func Scan(b *build.Build) (*core.Environment, error) {
 	s := scanner{
 		functions: make(chan *core.Function),
 		files:     make(chan *fs.File),
@@ -23,5 +23,38 @@ func Scan(b *build.Build) (<-chan *core.Function, <-chan *fs.File, <-chan error)
 		close(s.errors)
 	}()
 
-	return s.functions, s.files, s.errors
+	all := &core.Environment{
+		Files:     make([]*fs.File, 0, 8),
+		Functions: make(map[string]*core.Function, 32),
+	}
+
+	for s.functions != nil || s.files != nil || s.errors != nil {
+		select {
+		case f, ok := <-s.functions:
+			if !ok {
+				s.functions = nil
+				continue
+			}
+
+			all.Functions[f.String()] = f
+
+		case file, ok := <-s.files:
+			if !ok {
+				s.files = nil
+				continue
+			}
+
+			all.Files = append(all.Files, file)
+
+		case err, ok := <-s.errors:
+			if !ok {
+				s.errors = nil
+				continue
+			}
+
+			return all, err
+		}
+	}
+
+	return all, nil
 }
\ No newline at end of file
diff --git a/src/scanner/Scan_test.go b/src/scanner/Scan_test.go
index 1066652..407b63a 100644
--- a/src/scanner/Scan_test.go
+++ b/src/scanner/Scan_test.go
@@ -4,70 +4,24 @@ import (
 	"testing"
 
 	"git.urbach.dev/cli/q/src/build"
-	"git.urbach.dev/cli/q/src/core"
-	"git.urbach.dev/cli/q/src/fs"
 	"git.urbach.dev/cli/q/src/scanner"
 	"git.urbach.dev/go/assert"
 )
 
-func TestScanDirectory(t *testing.T) {
-	b := build.New("testdata")
-	functions, files, errors := scanner.Scan(b)
-	err := consume(t, functions, files, errors)
-	assert.Nil(t, err)
-}
-
-func TestScanFile(t *testing.T) {
-	b := build.New("testdata/file.q")
-	functions, files, errors := scanner.Scan(b)
-	err := consume(t, functions, files, errors)
-	assert.Nil(t, err)
-}
-
-func TestScanNotExisting(t *testing.T) {
+func TestNotExisting(t *testing.T) {
 	b := build.New("_")
-	functions, files, errors := scanner.Scan(b)
-	err := consume(t, functions, files, errors)
+	_, err := scanner.Scan(b)
 	assert.NotNil(t, err)
 }
 
+func TestMultiPlatform(t *testing.T) {
+	b := build.New("testdata/platforms")
+	_, err := scanner.Scan(b)
+	assert.Nil(t, err)
+}
+
 func TestScanHelloExample(t *testing.T) {
 	b := build.New("../../examples/hello")
-	functions, files, errors := scanner.Scan(b)
-	err := consume(t, functions, files, errors)
+	_, err := scanner.Scan(b)
 	assert.Nil(t, err)
-}
-
-func consume(t *testing.T, functions <-chan *core.Function, files <-chan *fs.File, errors <-chan error) error {
-	var lastError error
-
-	for functions != nil || files != nil || errors != nil {
-		select {
-		case function, ok := <-functions:
-			if !ok {
-				functions = nil
-				continue
-			}
-
-			t.Log(function)
-
-		case file, ok := <-files:
-			if !ok {
-				files = nil
-				continue
-			}
-
-			t.Log(file)
-
-		case err, ok := <-errors:
-			if !ok {
-				errors = nil
-				continue
-			}
-
-			lastError = err
-		}
-	}
-
-	return lastError
 }
\ No newline at end of file
diff --git a/src/scanner/errors_test.go b/src/scanner/errors_test.go
new file mode 100644
index 0000000..c98f1b8
--- /dev/null
+++ b/src/scanner/errors_test.go
@@ -0,0 +1,50 @@
+package scanner_test
+
+import (
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"git.urbach.dev/cli/q/src/build"
+	"git.urbach.dev/cli/q/src/errors"
+	"git.urbach.dev/cli/q/src/scanner"
+	"git.urbach.dev/go/assert"
+)
+
+var errs = []struct {
+	File          string
+	ExpectedError error
+}{
+	{"ExpectedFunctionDefinition.q", errors.ExpectedFunctionDefinition},
+	{"ExpectedPackageName.q", errors.ExpectedPackageName},
+	{"InvalidCharacter.q", &errors.InvalidCharacter{Character: "@"}},
+	{"InvalidCharacter2.q", &errors.InvalidCharacter{Character: "@"}},
+	{"InvalidCharacter3.q", &errors.InvalidCharacter{Character: "@"}},
+	{"InvalidCharacter4.q", &errors.InvalidCharacter{Character: "+++"}},
+	{"InvalidFunctionDefinition.q", errors.InvalidFunctionDefinition},
+	{"InvalidTopLevel.q", &errors.InvalidTopLevel{Instruction: "123"}},
+	{"InvalidTopLevel2.q", &errors.InvalidTopLevel{Instruction: "\"Hello\""}},
+	{"InvalidTopLevel3.q", &errors.InvalidTopLevel{Instruction: "+"}},
+	{"MissingBlockEnd.q", errors.MissingBlockEnd},
+	{"MissingBlockEnd2.q", errors.MissingBlockEnd},
+	{"MissingBlockStart.q", errors.MissingBlockStart},
+	{"MissingGroupEnd.q", errors.MissingGroupEnd},
+	{"MissingGroupStart.q", errors.MissingGroupStart},
+	{"MissingParameter.q", errors.MissingParameter},
+	{"MissingParameter2.q", errors.MissingParameter},
+	{"MissingParameter3.q", errors.MissingParameter},
+	{"MissingType.q", errors.MissingType},
+}
+
+func TestErrors(t *testing.T) {
+	for _, test := range errs {
+		name := strings.TrimSuffix(test.File, ".q")
+
+		t.Run(name, func(t *testing.T) {
+			b := build.New(filepath.Join("testdata", "errors", test.File))
+			_, err := scanner.Scan(b)
+			assert.NotNil(t, err)
+			assert.Contains(t, err.Error(), test.ExpectedError.Error())
+		})
+	}
+}
\ No newline at end of file
diff --git a/src/scanner/scanSignature.go b/src/scanner/scanSignature.go
index 4ec6ffb..e62e3cc 100644
--- a/src/scanner/scanSignature.go
+++ b/src/scanner/scanSignature.go
@@ -60,7 +60,7 @@ func scanSignature(file *fs.File, tokens token.List, i int, delimiter token.Kind
 			}
 
 			if paramsStart == -1 {
-				return nil, i, errors.New(errors.InvalidDefinition, file, tokens[i].Position)
+				return nil, i, errors.New(errors.InvalidFunctionDefinition, file, tokens[i].Position)
 			}
 
 			return nil, i, nil
@@ -71,7 +71,7 @@ func scanSignature(file *fs.File, tokens token.List, i int, delimiter token.Kind
 			continue
 		}
 
-		return nil, i, errors.New(errors.InvalidDefinition, file, tokens[i].Position)
+		return nil, i, errors.New(errors.InvalidFunctionDefinition, file, tokens[i].Position)
 	}
 
 	// Return type
diff --git a/src/scanner/testdata/errors/ExpectedFunctionDefinition.q b/src/scanner/testdata/errors/ExpectedFunctionDefinition.q
new file mode 100644
index 0000000..ac72fa7
--- /dev/null
+++ b/src/scanner/testdata/errors/ExpectedFunctionDefinition.q
@@ -0,0 +1 @@
+main()
\ No newline at end of file
diff --git a/src/scanner/testdata/errors/ExpectedPackageName.q b/src/scanner/testdata/errors/ExpectedPackageName.q
new file mode 100644
index 0000000..efca996
--- /dev/null
+++ b/src/scanner/testdata/errors/ExpectedPackageName.q
@@ -0,0 +1 @@
+import
\ No newline at end of file
diff --git a/src/scanner/testdata/errors/InvalidCharacter.q b/src/scanner/testdata/errors/InvalidCharacter.q
new file mode 100644
index 0000000..b516b2c
--- /dev/null
+++ b/src/scanner/testdata/errors/InvalidCharacter.q
@@ -0,0 +1 @@
+@
\ No newline at end of file
diff --git a/src/scanner/testdata/errors/InvalidCharacter2.q b/src/scanner/testdata/errors/InvalidCharacter2.q
new file mode 100644
index 0000000..f870343
--- /dev/null
+++ b/src/scanner/testdata/errors/InvalidCharacter2.q
@@ -0,0 +1 @@
+main@
\ No newline at end of file
diff --git a/src/scanner/testdata/errors/InvalidCharacter3.q b/src/scanner/testdata/errors/InvalidCharacter3.q
new file mode 100644
index 0000000..5f777b8
--- /dev/null
+++ b/src/scanner/testdata/errors/InvalidCharacter3.q
@@ -0,0 +1 @@
+main()@
\ No newline at end of file
diff --git a/src/scanner/testdata/errors/InvalidCharacter4.q b/src/scanner/testdata/errors/InvalidCharacter4.q
new file mode 100644
index 0000000..a97c489
--- /dev/null
+++ b/src/scanner/testdata/errors/InvalidCharacter4.q
@@ -0,0 +1,4 @@
+main() {
+	x := 123 +++ 456
+	syscall(60, x)
+}
\ No newline at end of file
diff --git a/src/scanner/testdata/errors/InvalidCondition.q b/src/scanner/testdata/errors/InvalidCondition.q
new file mode 100644
index 0000000..8d76be8
--- /dev/null
+++ b/src/scanner/testdata/errors/InvalidCondition.q
@@ -0,0 +1,3 @@
+main() {
+	if 42 {}
+}
\ No newline at end of file
diff --git a/src/scanner/testdata/errors/InvalidExpression.q b/src/scanner/testdata/errors/InvalidExpression.q
new file mode 100644
index 0000000..77e99f8
--- /dev/null
+++ b/src/scanner/testdata/errors/InvalidExpression.q
@@ -0,0 +1,3 @@
+main() {
+	syscall(+, -, *, /)
+}
\ No newline at end of file
diff --git a/src/scanner/testdata/errors/InvalidFunctionDefinition.q b/src/scanner/testdata/errors/InvalidFunctionDefinition.q
new file mode 100644
index 0000000..88d050b
--- /dev/null
+++ b/src/scanner/testdata/errors/InvalidFunctionDefinition.q
@@ -0,0 +1 @@
+main
\ No newline at end of file
diff --git a/src/scanner/testdata/errors/InvalidTopLevel.q b/src/scanner/testdata/errors/InvalidTopLevel.q
new file mode 100644
index 0000000..d800886
--- /dev/null
+++ b/src/scanner/testdata/errors/InvalidTopLevel.q
@@ -0,0 +1 @@
+123
\ No newline at end of file
diff --git a/src/scanner/testdata/errors/InvalidTopLevel2.q b/src/scanner/testdata/errors/InvalidTopLevel2.q
new file mode 100644
index 0000000..5638d8b
--- /dev/null
+++ b/src/scanner/testdata/errors/InvalidTopLevel2.q
@@ -0,0 +1 @@
+"Hello"
\ No newline at end of file
diff --git a/src/scanner/testdata/errors/InvalidTopLevel3.q b/src/scanner/testdata/errors/InvalidTopLevel3.q
new file mode 100644
index 0000000..9b26e9b
--- /dev/null
+++ b/src/scanner/testdata/errors/InvalidTopLevel3.q
@@ -0,0 +1 @@
++
\ No newline at end of file
diff --git a/src/scanner/testdata/errors/MissingBlockEnd.q b/src/scanner/testdata/errors/MissingBlockEnd.q
new file mode 100644
index 0000000..48a9f79
--- /dev/null
+++ b/src/scanner/testdata/errors/MissingBlockEnd.q
@@ -0,0 +1 @@
+main(){
\ No newline at end of file
diff --git a/src/scanner/testdata/errors/MissingBlockEnd2.q b/src/scanner/testdata/errors/MissingBlockEnd2.q
new file mode 100644
index 0000000..5562918
--- /dev/null
+++ b/src/scanner/testdata/errors/MissingBlockEnd2.q
@@ -0,0 +1,3 @@
+main() {
+	loop {
+}
\ No newline at end of file
diff --git a/src/scanner/testdata/errors/MissingBlockStart.q b/src/scanner/testdata/errors/MissingBlockStart.q
new file mode 100644
index 0000000..006988a
--- /dev/null
+++ b/src/scanner/testdata/errors/MissingBlockStart.q
@@ -0,0 +1 @@
+main()}
\ No newline at end of file
diff --git a/src/scanner/testdata/errors/MissingGroupEnd.q b/src/scanner/testdata/errors/MissingGroupEnd.q
new file mode 100644
index 0000000..189300d
--- /dev/null
+++ b/src/scanner/testdata/errors/MissingGroupEnd.q
@@ -0,0 +1 @@
+main(
\ No newline at end of file
diff --git a/src/scanner/testdata/errors/MissingGroupStart.q b/src/scanner/testdata/errors/MissingGroupStart.q
new file mode 100644
index 0000000..83e9712
--- /dev/null
+++ b/src/scanner/testdata/errors/MissingGroupStart.q
@@ -0,0 +1 @@
+main)
\ No newline at end of file
diff --git a/src/scanner/testdata/errors/MissingParameter.q b/src/scanner/testdata/errors/MissingParameter.q
new file mode 100644
index 0000000..a3247e3
--- /dev/null
+++ b/src/scanner/testdata/errors/MissingParameter.q
@@ -0,0 +1 @@
+f(,) {}
\ No newline at end of file
diff --git a/src/scanner/testdata/errors/MissingParameter2.q b/src/scanner/testdata/errors/MissingParameter2.q
new file mode 100644
index 0000000..827b8d8
--- /dev/null
+++ b/src/scanner/testdata/errors/MissingParameter2.q
@@ -0,0 +1 @@
+f(a int,) -> int { return a }
\ No newline at end of file
diff --git a/src/scanner/testdata/errors/MissingParameter3.q b/src/scanner/testdata/errors/MissingParameter3.q
new file mode 100644
index 0000000..839bf40
--- /dev/null
+++ b/src/scanner/testdata/errors/MissingParameter3.q
@@ -0,0 +1 @@
+f(,a int) {}
\ No newline at end of file
diff --git a/src/scanner/testdata/errors/MissingType.q b/src/scanner/testdata/errors/MissingType.q
new file mode 100644
index 0000000..214c35e
--- /dev/null
+++ b/src/scanner/testdata/errors/MissingType.q
@@ -0,0 +1 @@
+f(a) {}
\ No newline at end of file
diff --git a/src/scanner/testdata/file.q b/src/scanner/testdata/platforms/file.q
similarity index 100%
rename from src/scanner/testdata/file.q
rename to src/scanner/testdata/platforms/file.q
diff --git a/src/scanner/testdata/file_arm.q b/src/scanner/testdata/platforms/file_arm.q
similarity index 100%
rename from src/scanner/testdata/file_arm.q
rename to src/scanner/testdata/platforms/file_arm.q
diff --git a/src/scanner/testdata/file_custom.q b/src/scanner/testdata/platforms/file_custom.q
similarity index 100%
rename from src/scanner/testdata/file_custom.q
rename to src/scanner/testdata/platforms/file_custom.q
diff --git a/src/scanner/testdata/file_linux.q b/src/scanner/testdata/platforms/file_linux.q
similarity index 100%
rename from src/scanner/testdata/file_linux.q
rename to src/scanner/testdata/platforms/file_linux.q
diff --git a/src/scanner/testdata/file_mac.q b/src/scanner/testdata/platforms/file_mac.q
similarity index 100%
rename from src/scanner/testdata/file_mac.q
rename to src/scanner/testdata/platforms/file_mac.q
diff --git a/src/scanner/testdata/file_unix.q b/src/scanner/testdata/platforms/file_unix.q
similarity index 100%
rename from src/scanner/testdata/file_unix.q
rename to src/scanner/testdata/platforms/file_unix.q
diff --git a/src/scanner/testdata/file_windows.q b/src/scanner/testdata/platforms/file_windows.q
similarity index 100%
rename from src/scanner/testdata/file_windows.q
rename to src/scanner/testdata/platforms/file_windows.q
diff --git a/src/scanner/testdata/file_x86.q b/src/scanner/testdata/platforms/file_x86.q
similarity index 100%
rename from src/scanner/testdata/file_x86.q
rename to src/scanner/testdata/platforms/file_x86.q