Remove the word middleware (#1067)

* Rename middleware to plugin

first pass; mostly used 'sed', few spots where I manually changed
text.

This still builds a coredns binary.

* fmt error

* Rename AddMiddleware to AddPlugin

* Readd AddMiddleware to remain backwards compat

plugin/rewrite/condition_test.go

@@ -0,0 +1,102 @@
+package rewrite
+
+/*
+func TestConditions(t *testing.T) {
+	tests := []struct {
+		condition string
+		isTrue    bool
+	}{
+		{"a is b", false},
+		{"a is a", true},
+		{"a not b", true},
+		{"a not a", false},
+		{"a has a", true},
+		{"a has b", false},
+		{"ba has b", true},
+		{"bab has b", true},
+		{"bab has bb", false},
+		{"a not_has a", false},
+		{"a not_has b", true},
+		{"ba not_has b", false},
+		{"bab not_has b", false},
+		{"bab not_has bb", true},
+		{"bab starts_with bb", false},
+		{"bab starts_with ba", true},
+		{"bab starts_with bab", true},
+		{"bab ends_with bb", false},
+		{"bab ends_with bab", true},
+		{"bab ends_with ab", true},
+		{"a match *", false},
+		{"a match a", true},
+		{"a match .*", true},
+		{"a match a.*", true},
+		{"a match b.*", false},
+		{"ba match b.*", true},
+		{"ba match b[a-z]", true},
+		{"b0 match b[a-z]", false},
+		{"b0a match b[a-z]", false},
+		{"b0a match b[a-z]+", false},
+		{"b0a match b[a-z0-9]+", true},
+		{"a not_match *", true},
+		{"a not_match a", false},
+		{"a not_match .*", false},
+		{"a not_match a.*", false},
+		{"a not_match b.*", true},
+		{"ba not_match b.*", false},
+		{"ba not_match b[a-z]", false},
+		{"b0 not_match b[a-z]", true},
+		{"b0a not_match b[a-z]", true},
+		{"b0a not_match b[a-z]+", true},
+		{"b0a not_match b[a-z0-9]+", false},
+	}
+
+	for i, test := range tests {
+		str := strings.Fields(test.condition)
+		ifCond, err := NewIf(str[0], str[1], str[2])
+		if err != nil {
+			t.Error(err)
+		}
+		isTrue := ifCond.True(nil)
+		if isTrue != test.isTrue {
+			t.Errorf("Test %v: expected %v found %v", i, test.isTrue, isTrue)
+		}
+	}
+
+	invalidOperators := []string{"ss", "and", "if"}
+	for _, op := range invalidOperators {
+		_, err := NewIf("a", op, "b")
+		if err == nil {
+			t.Errorf("Invalid operator %v used, expected error.", op)
+		}
+	}
+
+	replaceTests := []struct {
+		url       string
+		condition string
+		isTrue    bool
+	}{
+		{"/home", "{uri} match /home", true},
+		{"/hom", "{uri} match /home", false},
+		{"/hom", "{uri} starts_with /home", false},
+		{"/hom", "{uri} starts_with /h", true},
+		{"/home/.hiddenfile", `{uri} match \/\.(.*)`, true},
+		{"/home/.hiddendir/afile", `{uri} match \/\.(.*)`, true},
+	}
+
+	for i, test := range replaceTests {
+		r, err := http.NewRequest("GET", test.url, nil)
+		if err != nil {
+			t.Error(err)
+		}
+		str := strings.Fields(test.condition)
+		ifCond, err := NewIf(str[0], str[1], str[2])
+		if err != nil {
+			t.Error(err)
+		}
+		isTrue := ifCond.True(r)
+		if isTrue != test.isTrue {
+			t.Errorf("Test %v: expected %v found %v", i, test.isTrue, isTrue)
+		}
+	}
+}
+*/