Add tests for reader.go

1 files changed, 178 insertions, 0 deletions

diff --git a/parser/reader_test.go b/parser/reader_test.go
new file mode 100644
index 0000000..f80f52c
--- /dev/null
+++ b/parser/reader_test.go
@@ -0,0 +1,178 @@
+package parser
+
+import (
+	"bufio"
+	"io"
+	"strings"
+	"testing"
+)
+
+func TestPeekRune(t *testing.T) {
+	s := "Ta’ Ħaġrat"
+	reader := reader{r: bufio.NewReader(strings.NewReader(s))}
+
+	for _, r := range s {
+		r1, err := reader.peekRune()
+		if err != nil && !(err == io.EOF && r == 't') {
+			t.Fatalf("reader.peekRune() failed with ‘%T’ at rune ‘%c’", err, r)
+		}
+
+		r2, _ := reader.readRune()
+		if r1 != r2 {
+			t.Fatalf("reader.peekRune() peaked ‘%c’ but the next read rune was ‘%c’", r1, r2)
+		}
+	}
+}
+
+func TestUnreadRune(t *testing.T) {
+	s := "Ta’ Ħaġrat"
+	reader := reader{r: bufio.NewReader(strings.NewReader(s))}
+
+	for range s {
+		r1, _ := reader.readRune()
+		if err := reader.unreadRune(); err != nil {
+			t.Fatalf("reader.unreadRune() failed with ‘%T’ when unreading rune ‘%c’", err, r1)
+		}
+		r2, _ := reader.readRune()
+		if r1 != r2 {
+			t.Fatalf("reader.readRune() returned ‘%c’ after unreading ‘%c’", r2, r1)
+		}
+	}
+}
+
+func TestUnreadRunePosTracking(t *testing.T) {
+	s := "Ta’ Ħaġrat\nIJsselmeer"
+	reader := reader{r: bufio.NewReader(strings.NewReader(s))}
+
+	for i := range []rune(s) {
+		r, _ := reader.readRune()
+
+		if err := reader.unreadRune(); err != nil {
+			t.Fatalf("reader.unreadRune() failed with ‘%T’ when unreading rune ‘%c’", err, r)
+		}
+
+		// Ensure we tracked the row correctly
+		switch {
+		case i < 11 && reader.pos.row != 0:
+			t.Fatalf("Expected reader to be on row 0 after unreading rune ‘%c’ but got row %d", r, reader.pos.row)
+		case i >= 11 && reader.pos.row != 1:
+			t.Fatalf("Expected reader to be on row 1 after unreading rune ‘%c’ but got row %d", r, reader.pos.row)
+		}
+
+		// Ensure we tracked the column correctly
+		switch {
+		case i < 11 && reader.pos.col != uint(i):
+			t.Fatalf("Expected reader to be on col %d after unreading rune ‘%c’ but got col %d", i, r, reader.pos.col)
+		case i == 11 && reader.pos.col != 0:
+			t.Fatalf("Expected reader to be on col 0 after unreading rune ‘\\n’ but got col %d", reader.pos.col)
+		case i > 11 && reader.pos.col != uint(i)-11:
+			t.Fatalf("Expected reader to be on col %d after unreading rune ‘%c’ but got col %d", i-10, r, reader.pos.col)
+		}
+
+		reader.readRune()
+	}
+}
+
+func TestReadRune(t *testing.T) {
+	s := "Ta’ Ħaġrat"
+	reader := reader{r: bufio.NewReader(strings.NewReader(s))}
+
+	for _, r1 := range s {
+		r2, err := reader.readRune()
+		if err != nil {
+			t.Fatalf("reader.readRune() failed with ‘%T’", err)
+		}
+		if r1 != r2 {
+			t.Fatalf("reader.readRune() read ‘%c’ but ‘%c’ was expected", r1, r2)
+		}
+	}
+
+	_, err := reader.readRune()
+	switch {
+	case err == nil:
+		t.Fatal("reader.readRune() expected to fail but didn’t")
+	case err != io.EOF:
+		t.Fatalf("reader.readRune() expected to fail with io.EOF but got ‘%T’", err)
+	}
+}
+
+func TestReadRunePosTracking(t *testing.T) {
+	s := "Ta’ Ħaġrat\nIJsselmeer"
+	line1 := true
+	reader := reader{r: bufio.NewReader(strings.NewReader(s))}
+
+	for i := range []rune(s) {
+		// Track the line we’re on
+		r, _ := reader.readRune()
+		if r == '\n' {
+			line1 = false
+		}
+
+		// Ensure we tracked the row correctly
+		switch {
+		case line1 && reader.pos.row != 0:
+			t.Fatalf("Expected reader to be on row 0 when reading rune ‘%c’ but got row %d", r, reader.pos.row)
+		case !line1 && reader.pos.row != 1:
+			t.Fatalf("Expected reader to be on row 1 when reading rune ‘%c’ but got row %d", r, reader.pos.row)
+		}
+
+		// Ensure we tracked the column correctly
+		switch {
+		case i < 10 && reader.pos.col != uint(i)+1:
+			t.Fatalf("Expected reader to be on col %d when reading rune ‘%c’ but got col %d", i, r, reader.pos.col)
+		case i == 10 && reader.pos.col != 0:
+			t.Fatalf("Expected reader to be on col 0 when reading rune ‘\\n’ but got col %d", reader.pos.col)
+		case i > 10 && reader.pos.col != uint(i)-10:
+			t.Fatalf("Expected reader to be on col %d when reading rune ‘%c’ but got col %d", i-10, r, reader.pos.col)
+		}
+	}
+}
+
+func TestReadNonSpaceRune(t *testing.T) {
+	s := "Ta’ Ħaġrat  \t\n IJsselmeer"
+	reader := reader{r: bufio.NewReader(strings.NewReader(s))}
+	readUntil := func(target rune) {
+		for {
+			if r, _ := reader.readRune(); r == target {
+				break
+			}
+		}
+	}
+	assertNext := func(target rune) {
+		if r, err := reader.readNonSpaceRune(); err != nil {
+			t.Fatalf("reader.readNonSpaceRune() failed with ‘%T’", err)
+		} else if r != target {
+			t.Fatalf("reader.readNonSpaceRune() expected to return ‘%c’ but returned ‘%c’", target, r)
+		}
+	}
+
+	readUntil('’')
+	assertNext('Ħ')
+	readUntil('t')
+	assertNext('IJ')
+}
+
+func TestSkipSpaces(t *testing.T) {
+	s := "Ta’ Ħaġrat  \t\n IJsselmeer"
+	reader := reader{r: bufio.NewReader(strings.NewReader(s))}
+	readUntil := func(target rune) {
+		for {
+			if r, _ := reader.readRune(); r == target {
+				break
+			}
+		}
+	}
+	assertNext := func(target rune) {
+		if err := reader.skipSpaces(); err != nil {
+			t.Fatalf("reader.skipSpaces() failed with ‘%T’", err)
+		}
+		if r, _ := reader.readRune(); r != target {
+			t.Fatalf("reader.readRune() expected to return ‘%c’ but returned ‘%c’", target, r)
+		}
+	}
+
+	readUntil('’')
+	assertNext('Ħ')
+	readUntil('t')
+	assertNext('IJ')
+}