diff --git a/analyzer/assignment_test.go b/analyzer/assignment_test.go
index 5353cd6..8b6c036 100644
--- a/analyzer/assignment_test.go
+++ b/analyzer/assignment_test.go
@@ -321,3 +321,15 @@ B:(& [g]:Int)
 }
 `)
 }
+
+func TestAssignmentErrConstant (test *testing.T) {
+testStringErr (test,
+"cannot assign to constant", 5, 2,
+`
+T: Int
+| x 0
+[main] = {
+	T.x = 5
+}
+`)
+}
diff --git a/analyzer/constant_test.go b/analyzer/constant_test.go
new file mode 100644
index 0000000..0b59f6d
--- /dev/null
+++ b/analyzer/constant_test.go
@@ -0,0 +1,90 @@
+package analyzer
+
+import "testing"
+
+func TestConstantValueSpecified (test *testing.T) {
+testString (test,
+`
+Weekday: Int
+| sunday 1
+| monday 2
+| tuesday 3
+| wednesday 4
+| thursday 5
+| friday 6
+| saturday 7
+
+[print s:String]
+[printWeekday w:Weekday] = [print switch w
+	| sunday    'sunday'
+	| monday    'monday'
+	| tuesday   'tuesday'
+	| wednesday 'wednesday'
+	| thursday  'thursday'
+	| friday    'friday'
+	| saturday  'saturday'
+	*           'unknown']
+[f] = [printWeekday Weekday.monday]
+`)}
+
+func TestConstantValueUnspecified (test *testing.T) {
+testString (test,
+`
+Weekday: Int
+| sunday
+| monday
+| tuesday
+| wednesday
+| thursday
+| friday
+| saturday
+
+[print s:String]
+[printWeekday w:Weekday] = [print switch w
+	| sunday    'sunday'
+	| monday    'monday'
+	| tuesday   'tuesday'
+	| wednesday 'wednesday'
+	| thursday  'thursday'
+	| friday    'friday'
+	| saturday  'saturday'
+	*           'unknown']
+[f] = [printWeekday Weekday.monday]
+`)}
+
+func TestConstantString (test *testing.T) {
+testString (test,
+`
+Weekday: String
+| sunday    'sunday'
+| monday    'monday'
+| tuesday   'tuesday'
+| wednesday 'wednesday'
+| thursday  'thursday'
+| friday    'friday'
+| saturday  'saturday'
+
+[print s:String]
+[printWeekday w:Weekday] = [print [~String w]]
+[f] = [printWeekday Weekday.monday]
+`)}
+
+// TODO: consider filling values for string constants by using the constant
+// name?
+func TestErrConstantStringUnspecified (test *testing.T) {
+testStringErr (test,
+"cannot fill in constant values for non-numeric type Weekday", 5, 11
+`
+Weekday: String
+| sunday
+| monday
+| tuesday
+| wednesday
+| thursday
+| friday
+| saturday
+
+[print s:String]
+[printWeekday w:Weekday] = [print [~String w]]
+[f] = [printWeekday Weekday.monday]
+`)}
diff --git a/analyzer/name_test.go b/analyzer/name_test.go
index 82c5ed8..f0c0711 100644
--- a/analyzer/name_test.go
+++ b/analyzer/name_test.go
@@ -203,3 +203,36 @@ Type: (. world:Int)
 }
 `)
 }
+
+func TestConstantNameErrMissing (test *testing.T) {
+testStringErr (test,
+"no constant Weekday.palday", 13, 21,
+`
+Weekday: String
+| sunday    'sunday'
+| monday    'monday'
+| tuesday   'tuesday'
+| wednesday 'wednesday'
+| thursday  'thursday'
+| friday    'friday'
+| saturday  'saturday'
+
+[print s:String]
+[printWeekday w:Weekday] = [print [~String w]]
+[f] = [printWeekday Weekday.palday]
+`)}
+
+func TestConstantUniqueErr (test *testing.T) {
+testStringErr (test,
+"Weekday.tuesday already defined at stream0.fspl:5:1", 8, 1,
+`
+Weekday: String
+| sunday    'sunday'
+| monday    'monday'
+| tuesday   'tuesday'
+| wednesday 'wednesday'
+| thursday  'thursday'
+| tuesday   'tuesday'
+| friday    'friday'
+| saturday  'saturday'
+`)}