diff --git a/src/FSharp.Control.TaskSeq.Test/TaskSeq.Append.Tests.fs b/src/FSharp.Control.TaskSeq.Test/TaskSeq.Append.Tests.fs
index 3201019..9311cab 100644
--- a/src/FSharp.Control.TaskSeq.Test/TaskSeq.Append.Tests.fs
+++ b/src/FSharp.Control.TaskSeq.Test/TaskSeq.Append.Tests.fs
@@ -93,8 +93,8 @@ module SideEffects =
         |> validateSequence
         |> Task.map (fun () -> i |> should equal 2)
 
-    [<Theory; ClassData(typeof<TestImmTaskSeq>)>]
-    let ``TaskSeq-appendSeq consumes whole sequence once incl after-effects`` variant =
+    [<Fact>]
+    let ``TaskSeq-appendSeq consumes whole sequence once incl after-effects`` () =
         let mutable i = 0
 
         let ts = taskSeq {
@@ -108,8 +108,8 @@ module SideEffects =
         |> validateSequence
         |> Task.map (fun () -> i |> should equal 2)
 
-    [<Theory; ClassData(typeof<TestImmTaskSeq>)>]
-    let ``TaskSeq-prependSeq consumes whole sequence once incl after-effects`` variant =
+    [<Fact>]
+    let ``TaskSeq-prependSeq consumes whole sequence once incl after-effects`` () =
         let mutable i = 0
 
         taskSeq {
diff --git a/src/FSharp.Control.TaskSeq.Test/TaskSeq.Except.Tests.fs b/src/FSharp.Control.TaskSeq.Test/TaskSeq.Except.Tests.fs
index db49b2c..9054abb 100644
--- a/src/FSharp.Control.TaskSeq.Test/TaskSeq.Except.Tests.fs
+++ b/src/FSharp.Control.TaskSeq.Test/TaskSeq.Except.Tests.fs
@@ -54,12 +54,14 @@ module EmptySeq =
     let ``TaskSeq-except no side effect in exclude seq if source seq is empty`` variant =
         let mutable i = 0
 
+        // argument of TaskSeq.exclude is only iterated once we get the first item
+        // from the input. With empty input, this is not evaluated
         let exclude = taskSeq {
-            i <- i + 1
+            i <- i + 1 // we test that we never get here
             yield 12
         }
 
-        TaskSeq.empty
+        Gen.getEmptyVariant variant
         |> TaskSeq.except exclude
         |> verifyEmpty
         |> Task.map (fun () -> i |> should equal 0) // exclude seq is only enumerated after first item in source
@@ -96,8 +98,8 @@ module Immutable =
         |> TaskSeq.except (Gen.getSeqImmutable variant)
         |> verifyEmpty
 
-    [<Theory; ClassData(typeof<TestImmTaskSeq>)>]
-    let ``TaskSeq-exceptOfSeq removes duplicates`` variant =
+    [<Fact>]
+    let ``TaskSeq-exceptOfSeq removes duplicates`` () =
         TaskSeq.ofList [ 1; 1; 2; 3; 4; 12; 12; 12; 13; 13; 13; 13; 13; 99 ]
         |> TaskSeq.exceptOfSeq [ 1..10 ]
         |> TaskSeq.toArrayAsync
diff --git a/src/FSharp.Control.TaskSeq.Test/TaskSeq.Pick.Tests.fs b/src/FSharp.Control.TaskSeq.Test/TaskSeq.Pick.Tests.fs
index e03c236..2b77392 100644
--- a/src/FSharp.Control.TaskSeq.Test/TaskSeq.Pick.Tests.fs
+++ b/src/FSharp.Control.TaskSeq.Test/TaskSeq.Pick.Tests.fs
@@ -126,8 +126,8 @@ module Immutable =
         twentyFive |> should equal "foo"
     }
 
-    [<Theory; ClassData(typeof<TestImmTaskSeq>)>]
-    let ``TaskSeq-pick happy path first item of seq`` variant = task {
+    [<Fact>]
+    let ``TaskSeq-pick happy path first item of seq`` () = task {
         let! first =
             Gen.sideEffectTaskSeqMicro 50L<µs> 1000L<µs> 50
             |> TaskSeq.pick (fun x -> if x = 1 then Some $"first{x}" else None) // dummy tasks seq starts at 1
diff --git a/src/FSharp.Control.TaskSeq.Test/TaskSeq.Realworld.fs b/src/FSharp.Control.TaskSeq.Test/TaskSeq.Realworld.fs
index ac9baee..33eed11 100644
--- a/src/FSharp.Control.TaskSeq.Test/TaskSeq.Realworld.fs
+++ b/src/FSharp.Control.TaskSeq.Test/TaskSeq.Realworld.fs
@@ -44,8 +44,6 @@ type AsyncBufferedReader(_output: ITestOutputHelper, data, blockSize) =
                 let! bytesRead = buffered.ReadAsync(mem, 0, mem.Length) // offset refers to offset in target buffer, not source
                 lastPos <- buffered.Position
 
-                let x: seq<Guid> = seq { 1 } |> Seq.cast
-
                 if bytesRead > 0 then
                     current <- ValueSome mem
                     return true
@@ -102,11 +100,14 @@ type ``Real world tests``(output: ITestOutputHelper) =
 
     [<Fact(Skip = "Broken test, faulty streaming test-implementation")>]
     let ``Reading a 10MB buffered IAsync stream from start to finish`` () = task {
+        // TODO: fix this test Remove underscores of the vars and rerun the test with
+        // all lined uncommented
         let mutable count = 0
-        use reader = AsyncBufferedReader(output, Array.init 2048 byte, 256)
+        use reader = new AsyncBufferedReader(output, Array.init 2048 byte, 256)
         let expected = Array.init 256 byte
 
-        let ts = taskSeq {
+        // TODO: use this
+        let _ts = taskSeq {
             for data in reader do
                 do count <- count + 1
 
@@ -116,7 +117,7 @@ type ``Real world tests``(output: ITestOutputHelper) =
                 yield data
         }
 
-        // the following is extremely slow, which is why we just use F#'s comparison instead
+        // the following is extremely slow in XUnit/FsUnit, which is why we just use F#'s comparison instead
         // Using this takes 67s, compared to 0.25s using normal F# comparison.
         // reader |> TaskSeq.toArray |> should equal expected // VERY SLOW!!
 
diff --git a/src/FSharp.Control.TaskSeq.Test/TaskSeq.ToXXX.Tests.fs b/src/FSharp.Control.TaskSeq.Test/TaskSeq.ToXXX.Tests.fs
index 082fe98..d43e87e 100644
--- a/src/FSharp.Control.TaskSeq.Test/TaskSeq.ToXXX.Tests.fs
+++ b/src/FSharp.Control.TaskSeq.Test/TaskSeq.ToXXX.Tests.fs
@@ -138,7 +138,7 @@ module SideEffects =
 
     [<Theory; ClassData(typeof<TestSideEffectTaskSeq>)>]
     let ``TaskSeq-toListAsync should execute side effects multiple times`` variant = task {
-        let tq = Gen.sideEffectTaskSeq 10
+        let tq = Gen.getSeqWithSideEffect variant
         let! (results1: list<_>) = tq |> TaskSeq.toListAsync
         let! (results2: list<_>) = tq |> TaskSeq.toListAsync
         results1 |> should equal [ 1..10 ]