From 0a97b9627e914bc05bcb57b83e7bf0dbe29eb820 Mon Sep 17 00:00:00 2001
From: Mateusz Drewniak <matmg24@gmail.com>
Date: Sun, 2 Jul 2023 09:50:27 +0200
Subject: [PATCH] Add lexer tests

---
 go.mod        |   1 +
 go.sum        |   2 +
 lexer_test.go | 118 ++++++++++++++++++++++++++++++++++++++++++++++++++
 render.go     |   2 -
 4 files changed, 121 insertions(+), 2 deletions(-)
 create mode 100644 lexer_test.go

diff --git a/go.mod b/go.mod
index 3ee29a32..d559da46 100644
--- a/go.mod
+++ b/go.mod
@@ -3,6 +3,7 @@ module github.com/elk-language/go-prompt
 go 1.14
 
 require (
+	github.com/google/go-cmp v0.5.9 // indirect
 	github.com/mattn/go-colorable v0.1.7
 	github.com/mattn/go-runewidth v0.0.9
 	github.com/mattn/go-tty v0.0.3
diff --git a/go.sum b/go.sum
index 768bf936..a0af5319 100644
--- a/go.sum
+++ b/go.sum
@@ -1,3 +1,5 @@
+github.com/google/go-cmp v0.5.9 h1:O2Tfq5qg4qc4AmwVlvv0oLiVAGB7enBSJ2x2DqQFi38=
+github.com/google/go-cmp v0.5.9/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/mattn/go-colorable v0.1.4/go.mod h1:U0ppj6V5qS13XJ6of8GYAs25YV2eR4EVcfRqFIhoBtE=
 github.com/mattn/go-colorable v0.1.7 h1:bQGKb3vps/j0E9GfJQ03JyhRuxsvdAanXlT9BTw3mdw=
 github.com/mattn/go-colorable v0.1.7/go.mod h1:u6P/XSegPjTcexA+o6vUJrdnUu04hMope9wVRipJSqc=
diff --git a/lexer_test.go b/lexer_test.go
new file mode 100644
index 00000000..b4ccd567
--- /dev/null
+++ b/lexer_test.go
@@ -0,0 +1,118 @@
+package prompt
+
+import (
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+	"github.com/google/go-cmp/cmp/cmpopts"
+)
+
+func TestEagerLexerNext(t *testing.T) {
+	tests := map[string]struct {
+		lexer *EagerLexer
+		want  Token
+		ok    bool
+	}{
+		"return the first token when at the beginning": {
+			lexer: &EagerLexer{
+				tokens: []Token{
+					&SimpleToken{lexeme: "foo"},
+					&SimpleToken{lexeme: "bar"},
+				},
+				currentIndex: 0,
+			},
+			want: &SimpleToken{lexeme: "foo"},
+			ok:   true,
+		},
+		"return the second token": {
+			lexer: &EagerLexer{
+				tokens: []Token{
+					&SimpleToken{lexeme: "foo"},
+					&SimpleToken{lexeme: "bar"},
+					&SimpleToken{lexeme: "baz"},
+				},
+				currentIndex: 1,
+			},
+			want: &SimpleToken{lexeme: "bar"},
+			ok:   true,
+		},
+		"return false when at the end": {
+			lexer: &EagerLexer{
+				tokens: []Token{
+					&SimpleToken{lexeme: "foo"},
+					&SimpleToken{lexeme: "bar"},
+					&SimpleToken{lexeme: "baz"},
+				},
+				currentIndex: 3,
+			},
+			want: nil,
+			ok:   false,
+		},
+	}
+
+	for name, tc := range tests {
+		t.Run(name, func(t *testing.T) {
+			got, ok := tc.lexer.Next()
+			opts := []cmp.Option{
+				cmp.AllowUnexported(SimpleToken{}, EagerLexer{}),
+			}
+			if diff := cmp.Diff(tc.want, got, opts...); diff != "" {
+				t.Fatalf(diff)
+			}
+			if diff := cmp.Diff(tc.ok, ok, opts...); diff != "" {
+				t.Fatalf(diff)
+			}
+		})
+	}
+}
+
+func charLex(s string) []Token {
+	var result []Token
+	for _, char := range s {
+		result = append(result, NewSimpleToken(0, string(char)))
+	}
+
+	return result
+}
+
+func TestEagerLexerInit(t *testing.T) {
+	tests := map[string]struct {
+		lexer *EagerLexer
+		input string
+		want  *EagerLexer
+	}{
+		"reset the lexer's state": {
+			lexer: &EagerLexer{
+				lexFunc: charLex,
+				tokens: []Token{
+					&SimpleToken{lexeme: "foo"},
+					&SimpleToken{lexeme: "bar"},
+				},
+				currentIndex: 2,
+			},
+			input: "foo",
+			want: &EagerLexer{
+				lexFunc: charLex,
+				tokens: []Token{
+					&SimpleToken{lexeme: "f"},
+					&SimpleToken{lexeme: "o"},
+					&SimpleToken{lexeme: "o"},
+				},
+				currentIndex: 0,
+			},
+		},
+	}
+
+	for name, tc := range tests {
+		t.Run(name, func(t *testing.T) {
+			tc.lexer.Init(tc.input)
+			opts := []cmp.Option{
+				cmp.AllowUnexported(SimpleToken{}, EagerLexer{}),
+				cmpopts.IgnoreFields(EagerLexer{}, "lexFunc"),
+			}
+			if diff := cmp.Diff(tc.want, tc.lexer, opts...); diff != "" {
+				t.Fatalf(diff)
+			}
+		})
+	}
+}
diff --git a/render.go b/render.go
index 57a5bc8d..e865d137 100644
--- a/render.go
+++ b/render.go
@@ -1,7 +1,6 @@
 package prompt
 
 import (
-	"fmt"
 	"runtime"
 	"strings"
 
@@ -258,7 +257,6 @@ func (r *Render) lex(lexer Lexer, input string) {
 		a := strings.SplitAfter(s, token.Lexeme())
 		s = strings.TrimPrefix(s, a[0])
 
-		fmt.Printf("%#v\n", token)
 		r.out.SetColor(token.Color(), r.inputBGColor, false)
 		r.out.WriteStr(a[0])
 	}