diff --git a/array_test.go b/array_test.go
index 1dda525..3a421cf 100644
--- a/array_test.go
+++ b/array_test.go
@@ -14,6 +14,11 @@ func TestFirstEmpty(t *testing.T) {
 	assertLength(t, sel.Nodes, 0)
 }
 
+func TestFirstInvalid(t *testing.T) {
+	sel := Doc().Find("").First()
+	assertLength(t, sel.Nodes, 0)
+}
+
 func TestFirstRollback(t *testing.T) {
 	sel := Doc().Find(".pvk-content")
 	sel2 := sel.First().End()
@@ -36,6 +41,11 @@ func TestLastEmpty(t *testing.T) {
 	assertLength(t, sel.Nodes, 0)
 }
 
+func TestLastInvalid(t *testing.T) {
+	sel := Doc().Find("").Last()
+	assertLength(t, sel.Nodes, 0)
+}
+
 func TestLastRollback(t *testing.T) {
 	sel := Doc().Find(".pvk-content")
 	sel2 := sel.Last().End()
@@ -63,6 +73,11 @@ func TestEqEmpty(t *testing.T) {
 	assertLength(t, sel.Nodes, 0)
 }
 
+func TestEqInvalid(t *testing.T) {
+	sel := Doc().Find("").Eq(0)
+	assertLength(t, sel.Nodes, 0)
+}
+
 func TestEqInvalidPositive(t *testing.T) {
 	sel := Doc().Find(".pvk-content").Eq(3)
 	assertLength(t, sel.Nodes, 0)
@@ -85,6 +100,16 @@ func TestSlice(t *testing.T) {
 	assertLength(t, sel.Nodes, 2)
 }
 
+func TestSliceEmpty(t *testing.T) {
+	sel := Doc().Find("x").Slice(0, 2)
+	assertLength(t, sel.Nodes, 0)
+}
+
+func TestSliceInvalid(t *testing.T) {
+	sel := Doc().Find("").Slice(0, 2)
+	assertLength(t, sel.Nodes, 0)
+}
+
 func TestSliceOutOfBounds(t *testing.T) {
 	defer assertPanic(t)
 	Doc().Find(".pvk-content").Slice(2, 12)
@@ -157,6 +182,13 @@ func TestIndexSelector(t *testing.T) {
 	}
 }
 
+func TestIndexSelectorInvalid(t *testing.T) {
+	sel := Doc().Find(".hero-unit")
+	if i := sel.IndexSelector(""); i != -1 {
+		t.Errorf("Expected index of -1, got %v.", i)
+	}
+}
+
 func TestIndexOfNode(t *testing.T) {
 	sel := Doc().Find("div.pvk-gutter")
 	if i := sel.IndexOfNode(sel.Nodes[1]); i != 1 {
diff --git a/expand_test.go b/expand_test.go
index cff6996..03f35bb 100644
--- a/expand_test.go
+++ b/expand_test.go
@@ -9,6 +9,16 @@ func TestAdd(t *testing.T) {
 	assertLength(t, sel.Nodes, 19)
 }
 
+func TestAddInvalid(t *testing.T) {
+	sel1 := Doc().Find("div.row-fluid")
+	sel2 := sel1.Add("")
+	assertLength(t, sel1.Nodes, 19)
+	assertLength(t, sel2.Nodes, 19)
+	if sel1 == sel2 {
+		t.Errorf("selections should not be the same")
+	}
+}
+
 func TestAddRollback(t *testing.T) {
 	sel := Doc().Find(".pvk-content")
 	sel2 := sel.Add("a").End()
diff --git a/filter.go b/filter.go
index f7e0704..c8d9825 100644
--- a/filter.go
+++ b/filter.go
@@ -12,8 +12,8 @@ func (s *Selection) Filter(selector string) *Selection {
 }
 
 // FilterMatcher reduces the set of matched elements to those that match
-// the given matcher.
-// It returns a new Selection object for this subset of matching elements.
+// the given matcher. It returns a new Selection object for this subset
+// of matching elements.
 func (s *Selection) FilterMatcher(m Matcher) *Selection {
 	return pushStack(s, winnow(s, m, true))
 }
diff --git a/filter_test.go b/filter_test.go
index d5978b5..f663c08 100644
--- a/filter_test.go
+++ b/filter_test.go
@@ -14,6 +14,11 @@ func TestFilterNone(t *testing.T) {
 	assertLength(t, sel.Nodes, 0)
 }
 
+func TestFilterInvalid(t *testing.T) {
+	sel := Doc().Find(".span12").Filter("")
+	assertLength(t, sel.Nodes, 0)
+}
+
 func TestFilterRollback(t *testing.T) {
 	sel := Doc().Find(".pvk-content")
 	sel2 := sel.Filter(".alert").End()
@@ -74,6 +79,11 @@ func TestNot(t *testing.T) {
 	assertLength(t, sel.Nodes, 1)
 }
 
+func TestNotInvalid(t *testing.T) {
+	sel := Doc().Find(".span12").Not("")
+	assertLength(t, sel.Nodes, 2)
+}
+
 func TestNotRollback(t *testing.T) {
 	sel := Doc().Find(".span12")
 	sel2 := sel.Not(".alert").End()
@@ -145,6 +155,11 @@ func TestHas(t *testing.T) {
 	// Has() returns the high-level .container-fluid div, and the one that is the immediate parent of center-content
 }
 
+func TestHasInvalid(t *testing.T) {
+	sel := Doc().Find(".container-fluid").Has("")
+	assertLength(t, sel.Nodes, 0)
+}
+
 func TestHasRollback(t *testing.T) {
 	sel := Doc().Find(".container-fluid")
 	sel2 := sel.Has(".center-content").End()
diff --git a/i114_test.go b/i114_test.go
deleted file mode 100644
index 038eff1..0000000
--- a/i114_test.go
+++ /dev/null
@@ -1,15 +0,0 @@
-package goquery
-
-import (
-	"strings"
-	"testing"
-)
-
-func TestIssue114(t *testing.T) {
-	d, err := NewDocumentFromReader(strings.NewReader("<html><head><title>some title</title></head><body><h1>H1</h1></body></html>"))
-	if err != nil {
-		t.Error(err)
-	}
-	sel := d.Find("~")
-	t.Log(sel)
-}
diff --git a/query_test.go b/query_test.go
index 2f40f42..54b2a2e 100644
--- a/query_test.go
+++ b/query_test.go
@@ -11,6 +11,13 @@ func TestIs(t *testing.T) {
 	}
 }
 
+func TestIsInvalid(t *testing.T) {
+	sel := Doc().Find(".footer p:nth-child(1)")
+	if sel.Is("") {
+		t.Error("Is should not succeed with invalid selector string")
+	}
+}
+
 func TestIsPositional(t *testing.T) {
 	sel := Doc().Find(".footer p:nth-child(2)")
 	if !sel.Is("p:nth-child(2)") {
diff --git a/traversal_test.go b/traversal_test.go
index 00fb5cd..59b17a8 100644
--- a/traversal_test.go
+++ b/traversal_test.go
@@ -21,9 +21,9 @@ func TestFindNotSelf(t *testing.T) {
 	assertLength(t, sel.Nodes, 0)
 }
 
-func TestFindInvalidSelector(t *testing.T) {
-	defer assertPanic(t)
-	Doc().Find(":+ ^")
+func TestFindInvalid(t *testing.T) {
+	sel := Doc().Find(":+ ^")
+	assertLength(t, sel.Nodes, 0)
 }
 
 func TestChainedFind(t *testing.T) {
@@ -31,6 +31,11 @@ func TestChainedFind(t *testing.T) {
 	assertLength(t, sel.Nodes, 4)
 }
 
+func TestChainedFindInvalid(t *testing.T) {
+	sel := Doc().Find("div.hero-unit").Find("")
+	assertLength(t, sel.Nodes, 0)
+}
+
 func TestChildren(t *testing.T) {
 	sel := Doc().Find(".pvk-content").Children()
 	assertLength(t, sel.Nodes, 5)
@@ -58,6 +63,11 @@ func TestChildrenFiltered(t *testing.T) {
 	assertLength(t, sel.Nodes, 1)
 }
 
+func TestChildrenFilteredInvalid(t *testing.T) {
+	sel := Doc().Find(".pvk-content").ChildrenFiltered("")
+	assertLength(t, sel.Nodes, 0)
+}
+
 func TestChildrenFilteredRollback(t *testing.T) {
 	sel := Doc().Find(".pvk-content")
 	sel2 := sel.ChildrenFiltered(".hero-unit").End()
@@ -69,6 +79,11 @@ func TestContentsFiltered(t *testing.T) {
 	assertLength(t, sel.Nodes, 1)
 }
 
+func TestContentsFilteredInvalid(t *testing.T) {
+	sel := Doc().Find(".pvk-content").ContentsFiltered("~")
+	assertLength(t, sel.Nodes, 0)
+}
+
 func TestContentsFilteredRollback(t *testing.T) {
 	sel := Doc().Find(".pvk-content")
 	sel2 := sel.ContentsFiltered(".hero-unit").End()
@@ -102,6 +117,11 @@ func TestParentFiltered(t *testing.T) {
 	assertClass(t, sel, "hero-unit")
 }
 
+func TestParentFilteredInvalid(t *testing.T) {
+	sel := Doc().Find(".container-fluid").ParentFiltered("")
+	assertLength(t, sel.Nodes, 0)
+}
+
 func TestParentFilteredRollback(t *testing.T) {
 	sel := Doc().Find(".container-fluid")
 	sel2 := sel.ParentFiltered(".hero-unit").End()
@@ -130,6 +150,11 @@ func TestParentsFiltered(t *testing.T) {
 	assertLength(t, sel.Nodes, 1)
 }
 
+func TestParentsFilteredInvalid(t *testing.T) {
+	sel := Doc().Find(".container-fluid").ParentsFiltered("")
+	assertLength(t, sel.Nodes, 0)
+}
+
 func TestParentsFilteredRollback(t *testing.T) {
 	sel := Doc().Find(".container-fluid")
 	sel2 := sel.ParentsFiltered("body").End()
@@ -141,6 +166,11 @@ func TestParentsUntil(t *testing.T) {
 	assertLength(t, sel.Nodes, 6)
 }
 
+func TestParentsUntilInvalid(t *testing.T) {
+	sel := Doc().Find(".container-fluid").ParentsUntil("")
+	assertLength(t, sel.Nodes, 666) // TODO : ?
+}
+
 func TestParentsUntilRollback(t *testing.T) {
 	sel := Doc().Find(".container-fluid")
 	sel2 := sel.ParentsUntil("body").End()
@@ -180,6 +210,11 @@ func TestParentsFilteredUntil(t *testing.T) {
 	assertLength(t, sel.Nodes, 2)
 }
 
+func TestParentsFilteredUntilInvalid(t *testing.T) {
+	sel := Doc().Find(".container-fluid").ParentsFilteredUntil("", "")
+	assertLength(t, sel.Nodes, 0)
+}
+
 func TestParentsFilteredUntilRollback(t *testing.T) {
 	sel := Doc().Find(".container-fluid")
 	sel2 := sel.ParentsFilteredUntil(".pvk-content", "body").End()
@@ -240,6 +275,11 @@ func TestSiblingsFiltered(t *testing.T) {
 	assertLength(t, sel.Nodes, 3)
 }
 
+func TestSiblingsFilteredInvalid(t *testing.T) {
+	sel := Doc().Find(".pvk-gutter").SiblingsFiltered("")
+	assertLength(t, sel.Nodes, 0)
+}
+
 func TestSiblingsFilteredRollback(t *testing.T) {
 	sel := Doc().Find(".pvk-gutter")
 	sel2 := sel.SiblingsFiltered(".pvk-content").End()
@@ -272,6 +312,11 @@ func TestNextFiltered(t *testing.T) {
 	assertLength(t, sel.Nodes, 2)
 }
 
+func TestNextFilteredInvalid(t *testing.T) {
+	sel := Doc().Find(".container-fluid").NextFiltered("")
+	assertLength(t, sel.Nodes, 0)
+}
+
 func TestNextFilteredRollback(t *testing.T) {
 	sel := Doc().Find(".container-fluid")
 	sel2 := sel.NextFiltered("div").End()
@@ -310,6 +355,11 @@ func TestPrevFiltered(t *testing.T) {
 	assertLength(t, sel.Nodes, 5)
 }
 
+func TestPrevFilteredInvalid(t *testing.T) {
+	sel := Doc().Find(".row-fluid").PrevFiltered("")
+	assertLength(t, sel.Nodes, 0)
+}
+
 func TestPrevFilteredRollback(t *testing.T) {
 	sel := Doc().Find(".row-fluid")
 	sel2 := sel.PrevFiltered(".row-fluid").End()
@@ -342,6 +392,11 @@ func TestNextAllFiltered(t *testing.T) {
 	assertLength(t, sel.Nodes, 2)
 }
 
+func TestNextAllFilteredInvalid(t *testing.T) {
+	sel := Doc().Find("#cf2 .row-fluid").NextAllFiltered("")
+	assertLength(t, sel.Nodes, 0)
+}
+
 func TestNextAllFilteredRollback(t *testing.T) {
 	sel := Doc().Find("#cf2 .row-fluid")
 	sel2 := sel.NextAllFiltered("[ng-cloak]").End()
@@ -380,6 +435,11 @@ func TestPrevAllFiltered(t *testing.T) {
 	assertLength(t, sel.Nodes, 3)
 }
 
+func TestPrevAllFilteredInvalid(t *testing.T) {
+	sel := Doc().Find(".pvk-gutter").PrevAllFiltered("")
+	assertLength(t, sel.Nodes, 0)
+}
+
 func TestPrevAllFilteredRollback(t *testing.T) {
 	sel := Doc().Find(".pvk-gutter")
 	sel2 := sel.PrevAllFiltered(".pvk-content").End()
@@ -392,6 +452,11 @@ func TestNextUntil(t *testing.T) {
 	assertSelectionIs(t, sel, "h4")
 }
 
+func TestNextUntilInvalid(t *testing.T) {
+	sel := Doc().Find(".alert a").NextUntil("")
+	assertLength(t, sel.Nodes, 100) // TODO : ?
+}
+
 func TestNextUntil2(t *testing.T) {
 	sel := Doc().Find("#cf2-1").NextUntil("[ng-cloak]")
 	assertLength(t, sel.Nodes, 1)
@@ -446,6 +511,11 @@ func TestPrevUntil(t *testing.T) {
 	assertSelectionIs(t, sel, "h4")
 }
 
+func TestPrevUntilInvalid(t *testing.T) {
+	sel := Doc().Find(".alert p").PrevUntil("")
+	assertLength(t, sel.Nodes, 100) // TODO : ?
+}
+
 func TestPrevUntil2(t *testing.T) {
 	sel := Doc().Find("[ng-cloak]").PrevUntil(":not([ng-cloak])")
 	assertLength(t, sel.Nodes, 1)
@@ -500,6 +570,11 @@ func TestNextFilteredUntil(t *testing.T) {
 	assertSelectionIs(t, sel, "#n3", "#n5", "#nf3", "#nf5")
 }
 
+func TestNextFilteredUntilInvalid(t *testing.T) {
+	sel := Doc2().Find(".two").NextFilteredUntil("", "")
+	assertLength(t, sel.Nodes, 0)
+}
+
 func TestNextFilteredUntilRollback(t *testing.T) {
 	sel := Doc2().Find(".two")
 	sel2 := sel.NextFilteredUntil(".even", ".six").End()
@@ -542,6 +617,11 @@ func TestPrevFilteredUntil(t *testing.T) {
 	assertSelectionIs(t, sel, "#n4", "#n2", "#nf4", "#nf2")
 }
 
+func TestPrevFilteredUntilInvalid(t *testing.T) {
+	sel := Doc2().Find(".five").PrevFilteredUntil("", "")
+	assertLength(t, sel.Nodes, 0)
+}
+
 func TestPrevFilteredUntilRollback(t *testing.T) {
 	sel := Doc2().Find(".four")
 	sel2 := sel.PrevFilteredUntil(".odd", ".one").End()
@@ -598,6 +678,12 @@ func TestClosestNone(t *testing.T) {
 	assertLength(t, sel2.Nodes, 0)
 }
 
+func TestClosestInvalid(t *testing.T) {
+	sel := Doc().Find("h4")
+	sel2 := sel.Closest("")
+	assertLength(t, sel2.Nodes, 0)
+}
+
 func TestClosestMany(t *testing.T) {
 	sel := Doc().Find(".container-fluid")
 	sel2 := sel.Closest(".pvk-content")