hclsyntax: Tests for static expression analysis behaviors

We previously lacked tests for our implementstions of
hcl.AbsTraversalForExpr, hcl.ExprList, and hcl.ExprMap. These are now
tested.

hcl/hclsyntax/expression_static_test.go

@@ -0,0 +1,131 @@
+package hclsyntax
+
+import (
+	"testing"
+
+	"github.com/go-test/deep"
+	"github.com/hashicorp/hcl2/hcl"
+	"github.com/zclconf/go-cty/cty"
+)
+
+func TestTraversalStatic(t *testing.T) {
+	expr, diags := ParseExpression([]byte(`a.b.c`), "", hcl.Pos{Line: 1, Column: 1})
+	got, moreDiags := hcl.AbsTraversalForExpr(expr)
+	diags = append(diags, moreDiags...)
+
+	if len(diags) != 0 {
+		t.Errorf("wrong number of diags %d; want 0", len(diags))
+		for _, diag := range diags {
+			t.Logf("- %s", diag)
+		}
+		return
+	}
+
+	want := hcl.Traversal{
+		hcl.TraverseRoot{
+			Name: "a",
+			SrcRange: hcl.Range{
+				Start: hcl.Pos{Line: 1, Column: 1, Byte: 0},
+				End:   hcl.Pos{Line: 1, Column: 2, Byte: 1},
+			},
+		},
+		hcl.TraverseAttr{
+			Name: "b",
+			SrcRange: hcl.Range{
+				Start: hcl.Pos{Line: 1, Column: 2, Byte: 1},
+				End:   hcl.Pos{Line: 1, Column: 4, Byte: 3},
+			},
+		},
+		hcl.TraverseAttr{
+			Name: "c",
+			SrcRange: hcl.Range{
+				Start: hcl.Pos{Line: 1, Column: 4, Byte: 3},
+				End:   hcl.Pos{Line: 1, Column: 6, Byte: 5},
+			},
+		},
+	}
+
+	for _, problem := range deep.Equal(got, want) {
+		t.Errorf(problem)
+	}
+}
+
+func TestTupleStatic(t *testing.T) {
+	expr, diags := ParseExpression([]byte(`[true, false]`), "", hcl.Pos{Line: 1, Column: 1})
+	exprs, moreDiags := hcl.ExprList(expr)
+	diags = append(diags, moreDiags...)
+	if len(diags) != 0 {
+		t.Errorf("wrong number of diags %d; want 0", len(diags))
+		for _, diag := range diags {
+			t.Logf("- %s", diag)
+		}
+		return
+	}
+
+	if got, want := len(exprs), 2; got != want {
+		t.Fatalf("wrong length %d; want %d", got, want)
+	}
+
+	got := make([]cty.Value, len(exprs))
+	want := []cty.Value{
+		cty.True,
+		cty.False,
+	}
+	for i, itemExpr := range exprs {
+		val, valDiags := itemExpr.Value(nil)
+		if len(valDiags) != 0 {
+			t.Errorf("wrong number of diags %d; want 0", len(valDiags))
+			for _, diag := range valDiags {
+				t.Logf("- %s", diag)
+			}
+			return
+		}
+		got[i] = val
+	}
+
+	for _, problem := range deep.Equal(got, want) {
+		t.Errorf(problem)
+	}
+}
+
+func TestMapStatic(t *testing.T) {
+	expr, diags := ParseExpression([]byte(`{"foo":true,"bar":false}`), "", hcl.Pos{Line: 1, Column: 1})
+	items, moreDiags := hcl.ExprMap(expr)
+	diags = append(diags, moreDiags...)
+	if len(diags) != 0 {
+		t.Errorf("wrong number of diags %d; want 0", len(diags))
+		for _, diag := range diags {
+			t.Logf("- %s", diag)
+		}
+		return
+	}
+
+	if got, want := len(items), 2; got != want {
+		t.Fatalf("wrong length %d; want %d", got, want)
+	}
+
+	got := make(map[cty.Value]cty.Value)
+	want := map[cty.Value]cty.Value{
+		cty.StringVal("foo"): cty.True,
+		cty.StringVal("bar"): cty.False,
+	}
+	for _, item := range items {
+		var itemDiags hcl.Diagnostics
+		key, keyDiags := item.Key.Value(nil)
+		itemDiags = append(itemDiags, keyDiags...)
+		val, valDiags := item.Value.Value(nil)
+		itemDiags = append(itemDiags, valDiags...)
+		if len(itemDiags) != 0 {
+			t.Errorf("wrong number of diags %d; want 0", len(itemDiags))
+			for _, diag := range itemDiags {
+				t.Logf("- %s", diag)
+			}
+			return
+		}
+		got[key] = val
+	}
+
+	for _, problem := range deep.Equal(got, want) {
+		t.Errorf(problem)
+	}
+}