Function TestUnifyExtendPositive

unionfind/unionfind_test.go:123–214

(t *testing.T)

}

func TestUnifyExtendPositive(t *testing.T) {
	tests := []struct {
		name string
		// The substitution that will be extended.
		base  map[ast.Variable]ast.BaseTerm
		left  []ast.BaseTerm
		right []ast.BaseTerm
		// Bindings that we want to see in the result.
		want map[ast.Variable]ast.BaseTerm
	}{
		{
			name:  "unify X = Y extending empty subst",
			base:  map[ast.Variable]ast.BaseTerm{},
			left:  []ast.BaseTerm{term("X")},
			right: []ast.BaseTerm{term("Y")},
			want: map[ast.Variable]ast.BaseTerm{
				ast.Variable{"X"}: term("Y"),
				ast.Variable{"Y"}: term("Y"),
			},
		},
		{
			name: "unify X = Y where X is already bound",
			base: map[ast.Variable]ast.BaseTerm{
				ast.Variable{"X"}: term("/c"),
			},
			left:  []ast.BaseTerm{term("X")},
			right: []ast.BaseTerm{term("Y")},
			want: map[ast.Variable]ast.BaseTerm{
				ast.Variable{"X"}: term("/c"),
				ast.Variable{"Y"}: term("/c"),
			},
		},
		{
			name: "unify X = Y where both X and Y were bound",
			base: map[ast.Variable]ast.BaseTerm{
				ast.Variable{"X"}: term("/c"),
				ast.Variable{"Y"}: term("X"),
			},
			left:  []ast.BaseTerm{term("X")},
			right: []ast.BaseTerm{term("Y")},
			want: map[ast.Variable]ast.BaseTerm{
				ast.Variable{"X"}: term("/c"),
				ast.Variable{"Y"}: term("/c"),
			},
		},
		{
			name: "unify X = Y where both X and Y were unified before",
			base: map[ast.Variable]ast.BaseTerm{
				ast.Variable{"X"}: term("Z"),
				ast.Variable{"Y"}: term("Z"),
			},
			left:  []ast.BaseTerm{term("X")},
			right: []ast.BaseTerm{term("/c")},
			want: map[ast.Variable]ast.BaseTerm{
				ast.Variable{"X"}: term("/c"),
				ast.Variable{"Y"}: term("/c"),
				ast.Variable{"Z"}: term("/c"),
			},