2 files changed, 80 insertions, 24 deletions

diff --git a/main/main.go b/main/main.go
index b7ef568..3a864ad 100644
--- a/main/main.go
+++ b/main/main.go
@@ -1,6 +1,7 @@
 package main
 
 import (
+	"io"
 	"os"
 	"bufio"
 	"main/walk"
@@ -15,32 +16,19 @@ type ProgramState struct {
 	pc int
 }
 
-func main() {
-	quiet := false
-	var input string
-	hasInput := false
-	
-	for i := 1; i < len(os.Args); i += 1 {
-		switch os.Args[i] {
-			case "-n":
-				quiet = true
-				continue
-		}
-		if i < len(os.Args) - 1 {
-			panic("Unexpected arguments after program")
-		}
-		input = os.Args[i]
-		hasInput = true
-	}
-	if !hasInput {
-		panic("Missing program")
-	}
+type config struct {
+	quiet bool
+	program string
+	in io.Reader
+	out io.Writer
+}
 
-	tokens := Lex(input)
+func run(config config) {
+	tokens := Lex(config.program)
 	program := Parse(tokens)
 
-	stdin := bufio.NewReader(os.Stdin)
-	stdout := bufio.NewWriter(os.Stdout)
+	stdin := bufio.NewReader(config.in)
+	stdout := bufio.NewWriter(config.out)
 
 	state := ProgramState {
 		in: json.NewJSONReader(stdin),
@@ -58,7 +46,7 @@ func main() {
 		for state.pc < len(state.program) {
 			state.program[state.pc].exec(&state)
 		}
-		if !quiet {
+		if !config.quiet {
 			for _, value := range state.value {
 				err := state.out.Write(value)
 				if err != nil {
@@ -71,3 +59,31 @@ func main() {
 	state.in.AssertDone()
 	state.out.AssertDone()
 }
+
+func main() {
+	config := config {
+		quiet: false,
+		in: os.Stdin,
+		out: os.Stdout,
+	}
+	hasInput := false
+	
+	for i := 1; i < len(os.Args); i += 1 {
+		switch os.Args[i] {
+			case "-n":
+				config.quiet = true
+				continue
+		}
+		if i < len(os.Args) - 1 {
+			panic("Unexpected arguments after program")
+		}
+		config.program = os.Args[i]
+		hasInput = true
+	}
+	if !hasInput {
+		panic("Missing program")
+	}
+
+	run(config)
+
+}
diff --git a/main/main_test.go b/main/main_test.go
new file mode 100644
index 0000000..a7a7795
--- /dev/null
+++ b/main/main_test.go
@@ -0,0 +1,40 @@
+package main
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestMain(t *testing.T) {
+	type test struct {
+		program string
+		quiet bool
+		input string
+		expected string
+	}
+
+	tests := []test {
+		{
+			program: `s/#(~(people)~$_@(1$_#(~(first_name)~$_.|(..$_){-0})-|(..$_){-0})-|(..$_){-0})-/p`,
+			quiet: true,
+			input: `{"something":{"nested":"Here is my test value"},"array":["Hello","world","these","are","values"],"people":[{"first_name":"Charlie","last_name":"Johnson","age":22},{"first_name":"Tom","last_name":"Johnson","age":18},{"first_name":"Charlie","last_name":"Chaplin","age":122},{"first_name":"John","last_name":"Johnson","age":48}]}`,
+			expected: `"Tom"`,
+		},
+	}
+
+	for i, test := range tests {
+		t.Logf("Running test: %d", i)
+
+		var output strings.Builder
+		run(config {
+			quiet: test.quiet,
+			program: test.program,
+			in: strings.NewReader(test.input),
+			out: &output,
+		})
+		
+		if output.String() != test.expected {
+			t.Errorf("Ran '%s' and expected %s but got %s", test.program, test.expected, output.String())
+		}
+	}
+}