Render Test for Render Instructions

1 files changed, 254 insertions, 0 deletions

diff --git a/internal/render/instructions_test.go b/internal/render/instructions_test.go
new file mode 100644
index 0000000..837a143
--- /dev/null
+++ b/internal/render/instructions_test.go
@@ -0,0 +1,254 @@
+package render
+
+import (
+	"testing"
+)
+
+const (
+	errFmt  = "Failed: '%v'\nExpected %v, got %v"
+	passFmt = "Passed: '%v'\n"
+)
+
+type testTrim struct {
+	title         string
+	input         Instruction
+	expectedReach string
+	n             int     // number of characters to trim
+	d             trimDir // FROM which side to trim
+	expected      Instruction
+}
+
+var TrimCases []testTrim = []testTrim{
+	{
+		"Trim 2 characters from the left",
+		DrawInstruction{X: 5, Y: 5, Content: "hello"},
+		"\033[5;5H",
+		2,
+		TrimLeft,
+		DrawInstruction{X: 7, Y: 5, Content: "llo"},
+	},
+	{
+		"Trim 2 characters from the right",
+		DrawInstruction{X: 43, Y: 6, Content: "hello"},
+		"\033[6;43H",
+		2,
+		TrimRight,
+		DrawInstruction{X: 43, Y: 6, Content: "hel"},
+	},
+	{
+		"Trim 2 characters from the left of a Clear",
+		ClearInstruction{X: 8, Y: 4, Size: 5},
+		"\033[4;8H",
+		2,
+		TrimLeft,
+		ClearInstruction{X: 10, Y: 4, Size: 3},
+	},
+	{
+		"Trim 2 characters from the right of a Clear",
+		ClearInstruction{X: 98, Y: 76, Size: 5},
+		"\033[76;98H",
+		2,
+		TrimRight,
+		ClearInstruction{X: 98, Y: 76, Size: 3},
+	},
+	{
+		"Trim 10 characters from the left of a Clear of size 5",
+		ClearInstruction{X: 42, Y: 69, Size: 5},
+		"\033[69;42H",
+		10,
+		TrimLeft,
+		nil,
+	},
+	{
+		"Trim 10 characters from the right of a Draw of size 5",
+		DrawInstruction{X: 420, Y: 1337, Content: "hello"},
+		"\033[1337;420H",
+		10,
+		TrimRight,
+		nil,
+	},
+}
+
+type testOverlap struct {
+	title       string
+	over, under Instruction
+	overlap     overlapType
+	expected    []Instruction
+}
+
+var OverlapCases []testOverlap = []testOverlap{
+	{
+		"Two draws that perfectly overlap",
+		DrawInstruction{X: 5, Y: 5, Content: "hello"},
+		DrawInstruction{X: 5, Y: 5, Content: "wadup"},
+		CoverTotal,
+		[]Instruction{},
+	},
+	{
+		"Draw + Clear that perfectly overlap",
+		DrawInstruction{X: 5, Y: 5, Content: "hello"},
+		ClearInstruction{X: 5, Y: 5, Size: 5},
+		CoverTotal,
+		[]Instruction{},
+	},
+	{
+		"Two Clears that perfectly overlap",
+		ClearInstruction{X: 5, Y: 5, Size: 5},
+		ClearInstruction{X: 5, Y: 5, Size: 5},
+		CoverTotal,
+		[]Instruction{},
+	},
+	{
+		"Draw 'More than covers' Clear",
+		DrawInstruction{X: 5, Y: 5, Content: "hello"},
+		ClearInstruction{X: 7, Y: 5, Size: 3},
+		CoverTotal,
+		[]Instruction{},
+	},
+	{
+		"Clear Squashes Draw on the left",
+		ClearInstruction{X: 2, Y: 5, Size: 5},
+		DrawInstruction{X: 5, Y: 5, Content: "qwertyuiop"},
+		CoverLeft,
+		[]Instruction{
+			DrawInstruction{X: 7, Y: 5, Content: "ertyuiop"},
+		},
+	},
+	{
+		"Clear Squashes Draw on the right",
+		ClearInstruction{X: 5, Y: 5, Size: 10},
+		DrawInstruction{X: 2, Y: 5, Content: "qwertyuiop"},
+		CoverRight,
+		[]Instruction{
+			DrawInstruction{X: 2, Y: 5, Content: "qwe"},
+		},
+	},
+	{
+		"Draw is within another Draw",
+		DrawInstruction{X: 7, Y: 5, Content: "yo"},
+		DrawInstruction{X: 5, Y: 5, Content: "hello"},
+		CoverWithin,
+		[]Instruction{
+			DrawInstruction{X: 5, Y: 5, Content: "he"},
+			DrawInstruction{X: 9, Y: 5, Content: "o"},
+		},
+	},
+	{
+		"Clear is within another Draw",
+		ClearInstruction{X: 10, Y: 5, Size: 5},
+		DrawInstruction{X: 5, Y: 5, Content: "TheQuickBrownFoxJumpsOverTheLazyDog"},
+		CoverWithin,
+		[]Instruction{
+			DrawInstruction{X: 5, Y: 5, Content: "TheQu"},
+			DrawInstruction{X: 15, Y: 5, Content: "ownFoxJumpsOverTheLazyDog"},
+		},
+	},
+
+	{
+		"Two Draws that don't overlap but are on the same row",
+		DrawInstruction{X: 5, Y: 5, Content: "hello"},
+		DrawInstruction{X: 55, Y: 5, Content: "greetings"},
+		CoverNone,
+		[]Instruction{
+			DrawInstruction{X: 55, Y: 5, Content: "greetings"},
+		},
+	},
+	{
+		"Two Clears on different rows",
+		ClearInstruction{X: 5, Y: 5, Size: 5},
+		ClearInstruction{X: 5, Y: 12, Size: 5},
+		CoverNone,
+		[]Instruction{
+			ClearInstruction{X: 5, Y: 12, Size: 5},
+		},
+	},
+}
+
+func InstructionEquals(a, b Instruction) bool {
+	var drwA, drwB DrawInstruction
+	drwAOk, clrAOk := false, false
+	var clrA, clrB ClearInstruction
+	switch a := a.(type) {
+	case DrawInstruction:
+		drwA = a
+		drwAOk = true
+	case ClearInstruction:
+		clrA = a
+		clrAOk = true
+
+	}
+	switch b := b.(type) {
+	case DrawInstruction:
+		drwB = b
+		if clrAOk { // A is of opposite type (clear)
+			return false
+		}
+	case ClearInstruction:
+		clrB = b
+		if drwAOk { // A is of opposite type (draw)
+			return false
+		}
+	}
+	// If both are draws
+	if drwAOk {
+		if drwA.Content != drwB.Content {
+			return false
+		}
+		if drwA.X != drwB.X || drwA.Y != drwB.Y {
+			return false
+		}
+	}
+	// If both are clears
+	if clrAOk {
+		if clrA.Size != clrB.Size {
+			return false
+		}
+		if clrA.X != clrB.X || clrA.Y != clrB.Y {
+			return false
+		}
+	}
+	return true
+}
+
+func TestTrim(t *testing.T) {
+	for _, tc := range TrimCases {
+		result := tc.input.Trim(tc.n, tc.d)
+		if !InstructionEquals(result, tc.expected) {
+			t.Errorf(errFmt, tc.title, tc.expected, result)
+		}
+		t.Logf(passFmt, tc.title)
+	}
+}
+
+func TestReach(t *testing.T) {
+	for _, tc := range TrimCases {
+		if r := reach(tc.input); r != tc.expectedReach {
+			t.Errorf(errFmt, tc.title, tc.expectedReach, r)
+		}
+		t.Logf(passFmt, tc.title)
+	}
+}
+
+func TestOverlap(t *testing.T) {
+	for _, tc := range OverlapCases {
+		if ot := overlap(tc.over, tc.under); ot != tc.overlap {
+			t.Errorf(errFmt, tc.title, tc.overlap, ot)
+		}
+		t.Logf(passFmt, tc.title)
+	}
+}
+
+func TestSquash(t *testing.T) {
+	for _, tc := range OverlapCases {
+		res := squash(tc.over, tc.under, tc.overlap)
+		if len(res) != len(tc.expected) {
+			t.Errorf(errFmt, tc.title, len(tc.expected), len(res))
+		}
+		for i, r := range res {
+			if !InstructionEquals(r, tc.expected[i]) {
+				t.Errorf(errFmt, tc.title, tc.expected[i], r)
+			}
+		}
+		t.Logf(passFmt, tc.title)
+	}
+}