diff --git a/core/execute_test.go b/core/execute_test.go
index 6a25b43..3bee29c 100644
--- a/core/execute_test.go
+++ b/core/execute_test.go
@@ -6,19 +6,19 @@ import (
 )
 
 func TestExecute(t *testing.T) {
-	assertLen := func(items []Item, length int) {
+	assertLen := func(t *testing.T, items []Item, length int) {
 		t.Helper()
 		if len(items) != length {
 			t.Fatalf("Expected %d items, got %d", length, len(items))
 		}
 	}
-	assertNil := func(err error) {
+	assertNil := func(t *testing.T, err error) {
 		t.Helper()
 		if err != nil {
 			t.Fatal(err)
 		}
 	}
-	assertNotNil := func(err error) {
+	assertNotNil := func(t *testing.T, err error) {
 		t.Helper()
 		if err == nil {
 			t.Fatal("expected err")
@@ -29,138 +29,165 @@ func TestExecute(t *testing.T) {
 		return item, err
 	}
 
-	res, err := execute([]string{"true"})
-	assertNil(err)
-	assertLen(res, 0)
-
-	// Exit with error code
-	res, err = execute([]string{"false"})
-	assertNotNil(err)
-	assertLen(res, 0)
-
-	res, err = execute([]string{"sh", "-c", "exit 22"})
-	assertNotNil(err)
-	assertLen(res, 0)
-
-	// Timeout
-	res, _, err = Execute("_", []string{"sleep", "10"}, nil, nil, "", time.Millisecond, nil)
-	assertNotNil(err)
-	assertLen(res, 0)
-
-	// Returning items
-	res, err = execute([]string{"jq", "-cn", `{id: "foo"}`})
-	assertNil(err)
-	assertLen(res, 1)
-	if res[0].Id != "foo" {
-		t.Fatal("jq -cn test failed")
-	}
-
-	// Read from stdin
-	res, _, err = Execute("_", []string{"jq", "-cR", `{id: .}`}, nil, nil, "bar", time.Minute, nil)
-	assertNil(err)
-	assertLen(res, 1)
-	if res[0].Id != "bar" {
-		t.Fatal("jq -cR test failed")
-	}
-
-	// Set env
-	res, _, err = Execute("_", []string{"jq", "-cn", `{id: env.HELLO}`}, []string{"HELLO=baz"}, nil, "", time.Minute, nil)
-	assertNil(err)
-	assertLen(res, 1)
-	if res[0].Id != "baz" {
-		t.Fatal("jq -cn env test failed")
-	}
-
-	// With logging on stderr
-	res, err = execute([]string{"sh", "-c", `echo 1>&2 Hello; jq -cn '{id: "box"}'; echo 1>&2 World`})
-	assertNil(err)
-	assertLen(res, 1)
-	if res[0].Id != "box" {
-		t.Fatal("stderr test failed")
-	}
-
-	// Unsupported item field is silently discarded
-	res, err = execute([]string{"jq", "-cn", `{id: "test", unknownField: "what is this"}`})
-	assertNil(err)
-	assertLen(res, 1)
-
-	// Field with incorrect type fails
-	res, err = execute([]string{"jq", "-cn", `{id: ["list"]}`})
-	assertNotNil(err)
-	assertLen(res, 0)
-
-	res, err = execute([]string{"jq", "-cn", `{id: "test", time: "0"}`})
-	assertNotNil(err)
-	assertLen(res, 0)
-
-	res, err = execute([]string{"jq", "-cn", `{id: null}`})
-	assertNotNil(err)
-	assertLen(res, 0)
-
-	// Items with duplicate ids is not a fetch error, but it will fail to update
-	res, err = execute([]string{"jq", "-cn", `["a", "a"] | .[] | {id: .}`})
-	assertNil(err)
-	assertLen(res, 2)
-
-	// Action keys are detected even with empty values
-	res, err = execute([]string{"jq", "-cn", `{id: "test", action: {"hello": null}}`})
-	assertNil(err)
-	assertLen(res, 1)
-	if res[0].Action["hello"] == nil {
-		t.Fatal("missing hello action")
-	}
-	if res[0].Action["goodbye"] != nil {
-		t.Fatal("nonexistent action should key to nil in Action")
-	}
-
-	res, err = execute([]string{"jq", "-cn", `{id: "test", action: {"hello": ""}}`})
-	assertNil(err)
-	assertLen(res, 1)
-	if res[0].Action["hello"] == nil {
-		t.Fatal("missing hello action")
-	}
-
-	res, err = execute([]string{"jq", "-cn", `{id: "test", action: {"hello": []}}`})
-	assertNil(err)
-	assertLen(res, 1)
-	if res[0].Action["hello"] == nil {
-		t.Fatal("missing hello action")
-	}
-
-	res, err = execute([]string{"jq", "-cn", `{id: "test", action: {"hello": {}}}`})
-	assertNil(err)
-	assertLen(res, 1)
-	if res[0].Action["hello"] == nil {
-		t.Fatal("missing hello action")
-	}
-
-	// Read state
-	argv := []string{"sh", "-c", `cat $STATE_PATH | jq -cR '{id: "greeting", title: .} | .title = "Hello " + .title'`}
-	res, _, err = Execute("_", argv, nil, []byte("world"), "", time.Minute, nil)
-	assertNil(err)
-	assertLen(res, 1)
-	if res[0].Title != "Hello world" {
-		t.Fatalf("expected 'Hello world' from read state, got '%s'", res[0].Title)
-	}
-
-	// Write state
-	argv = []string{"sh", "-c", `printf "Hello world" > $STATE_PATH; jq -cn '{id: "test"}'`}
-	res, newState, err := Execute("_", argv, nil, nil, "", time.Minute, nil)
-	assertNil(err)
-	assertLen(res, 1)
-	if string(newState) != "Hello world" {
-		t.Fatalf("expected 'Hello world' from write state, got %s", string(newState))
-	}
-
-	// Postprocessing function
-	argv = []string{"jq", "-cn", `{id: "foo"}`}
-	res, _, err = Execute("_", argv, nil, nil, "", time.Minute, func(item Item) Item {
-		item.Ttl = 123456
-		return item
+	t.Run("Noop", func(t *testing.T) {
+		res, err := execute([]string{"true"})
+		assertNil(t, err)
+		assertLen(t, res, 0)
+	})
+
+	t.Run("ExitWithErrorCode", func(t *testing.T) {
+		res, err := execute([]string{"false"})
+		assertNotNil(t, err)
+		assertLen(t, res, 0)
+	})
+
+	t.Run("ExitWithSpecificErrorCode", func(t *testing.T) {
+		res, err := execute([]string{"sh", "-c", "exit 22"})
+		assertNotNil(t, err)
+		assertLen(t, res, 0)
+	})
+
+	t.Run("Timeout", func(t *testing.T) {
+		res, _, err := Execute("_", []string{"sleep", "10"}, nil, nil, "", time.Millisecond, nil)
+		assertNotNil(t, err)
+		assertLen(t, res, 0)
+	})
+
+	t.Run("ReturningItems", func(t *testing.T) {
+		res, err := execute([]string{"jq", "-cn", `{id: "foo"}`})
+		assertNil(t, err)
+		assertLen(t, res, 1)
+		if res[0].Id != "foo" {
+			t.Fatal("jq -cn test failed")
+		}
+	})
+
+	t.Run("ReadFromStdin", func(t *testing.T) {
+		res, _, err := Execute("_", []string{"jq", "-cR", `{id: .}`}, nil, nil, "bar", time.Minute, nil)
+		assertNil(t, err)
+		assertLen(t, res, 1)
+		if res[0].Id != "bar" {
+			t.Fatal("jq -cR test failed")
+		}
+	})
+
+	t.Run("SetEnv", func(t *testing.T) {
+		res, _, err := Execute("_", []string{"jq", "-cn", `{id: env.HELLO}`}, []string{"HELLO=baz"}, nil, "", time.Minute, nil)
+		assertNil(t, err)
+		assertLen(t, res, 1)
+		if res[0].Id != "baz" {
+			t.Fatal("jq -cn env test failed")
+		}
+	})
+	t.Run("StderrLogging", func(t *testing.T) {
+		res, err := execute([]string{"sh", "-c", `echo 1>&2 Hello; jq -cn '{id: "box"}'; echo 1>&2 World`})
+		assertNil(t, err)
+		assertLen(t, res, 1)
+		if res[0].Id != "box" {
+			t.Fatal("stderr test failed")
+		}
+	})
+
+	t.Run("UnknownFieldIgnored", func(t *testing.T) {
+		res, err := execute([]string{"jq", "-cn", `{id: "test", unknownField: "what is this"}`})
+		assertNil(t, err)
+		assertLen(t, res, 1)
+	})
+
+	t.Run("IncorrectIdType", func(t *testing.T) {
+		res, err := execute([]string{"jq", "-cn", `{id: ["list"]}`})
+		assertNotNil(t, err)
+		assertLen(t, res, 0)
+	})
+
+	t.Run("IncorrectTimeType", func(t *testing.T) {
+		res, err := execute([]string{"jq", "-cn", `{id: "test", time: "0"}`})
+		assertNotNil(t, err)
+		assertLen(t, res, 0)
+	})
+
+	t.Run("NullId", func(t *testing.T) {
+		res, err := execute([]string{"jq", "-cn", `{id: null}`})
+		assertNotNil(t, err)
+		assertLen(t, res, 0)
+	})
+
+	// TODO maybe this *should* be an Execute error, via a map[string]bool
+	t.Run("DuplicateItemIds", func(t *testing.T) {
+		res, err := execute([]string{"jq", "-cn", `["a", "a"] | .[] | {id: .}`})
+		assertNil(t, err)
+		assertLen(t, res, 2)
+	})
+
+	t.Run("ActionNullValueOk", func(t *testing.T) {
+		res, err := execute([]string{"jq", "-cn", `{id: "test", action: {"hello": null}}`})
+		assertNil(t, err)
+		assertLen(t, res, 1)
+		if res[0].Action["hello"] == nil {
+			t.Fatal("missing hello action")
+		}
+		if res[0].Action["goodbye"] != nil {
+			t.Fatal("nonexistent action should key to nil in Action")
+		}
+	})
+
+	t.Run("ActionEmptyStringOk", func(t *testing.T) {
+		res, err := execute([]string{"jq", "-cn", `{id: "test", action: {"hello": ""}}`})
+		assertNil(t, err)
+		assertLen(t, res, 1)
+		if res[0].Action["hello"] == nil {
+			t.Fatal("missing hello action")
+		}
+	})
+
+	t.Run("ActionEmptyArrayOk", func(t *testing.T) {
+		res, err := execute([]string{"jq", "-cn", `{id: "test", action: {"hello": []}}`})
+		assertNil(t, err)
+		assertLen(t, res, 1)
+		if res[0].Action["hello"] == nil {
+			t.Fatal("missing hello action")
+		}
+	})
+
+	t.Run("ActionEmptyObjectOk", func(t *testing.T) {
+		res, err := execute([]string{"jq", "-cn", `{id: "test", action: {"hello": {}}}`})
+		assertNil(t, err)
+		assertLen(t, res, 1)
+		if res[0].Action["hello"] == nil {
+			t.Fatal("missing hello action")
+		}
+	})
+
+	t.Run("ReadState", func(t *testing.T) {
+		argv := []string{"sh", "-c", `cat $STATE_PATH | jq -cR '{id: "greeting", title: .} | .title = "Hello " + .title'`}
+		res, _, err := Execute("_", argv, nil, []byte("world"), "", time.Minute, nil)
+		assertNil(t, err)
+		assertLen(t, res, 1)
+		if res[0].Title != "Hello world" {
+			t.Fatalf("expected 'Hello world' from read state, got '%s'", res[0].Title)
+		}
+	})
+
+	t.Run("WriteState", func(t *testing.T) {
+		argv := []string{"sh", "-c", `printf "Hello world" > $STATE_PATH; jq -cn '{id: "test"}'`}
+		res, newState, err := Execute("_", argv, nil, nil, "", time.Minute, nil)
+		assertNil(t, err)
+		assertLen(t, res, 1)
+		if string(newState) != "Hello world" {
+			t.Fatalf("expected 'Hello world' from write state, got %s", string(newState))
+		}
+	})
+
+	t.Run("PostprocessSetTtl", func(t *testing.T) {
+		argv := []string{"jq", "-cn", `{id: "foo"}`}
+		res, _, err := Execute("_", argv, nil, nil, "", time.Minute, func(item Item) Item {
+			item.Ttl = 123456
+			return item
+		})
+		assertNil(t, err)
+		assertLen(t, res, 1)
+		if res[0].Ttl != 123456 {
+			t.Fatalf("expected ttl to be set to 123456, got %d", res[0].Ttl)
+		}
 	})
-	assertNil(err)
-	assertLen(res, 1)
-	if res[0].Ttl != 123456 {
-		t.Fatalf("expected ttl to be set to 123456, got %d", res[0].Ttl)
-	}
 }