refactoring: made input injectable for testing purposes

src/fakeinput.h

@@ -0,0 +1,6 @@
+// fakeinput.h exists solely for testing purposes
+// fakeInput is set by unit tests to inject specific inputs for testing
+#ifndef FAKEINPUT_H
+#define FAKEINPUT_H
+extern char **fakeInput;
+#endif

src/userinput.c

@@ -1,4 +1,5 @@
 #include "userinput.h"
+#include "fakeinput.h"
 
 #include <ctype.h>
 #include <stdio.h>
@@ -9,6 +10,8 @@
 #include <limits.h>
 #include <float.h>
 
+char **fakeInput = NULL;
+
 #define LD(name)\
     long double name##ldvalue;\
     long double *name##ld = NULL;\
@@ -39,6 +42,16 @@ void trimRight(char *input) {
 }
 
 char *readInput() {
+    if (fakeInput != NULL) {
+        if (fakeInput[0] == NULL) {
+            printf("The given list of inputs in the test was exceeded!\n");
+            exit(1);
+        }
+        char *result = malloc(strlen(fakeInput[0])*sizeof(char) + 1);
+        strcpy(result, fakeInput[0]);
+        fakeInput = fakeInput + 1;
+        return result;
+    }
     size_t bufferSize = 100;
     char *buffer = malloc(bufferSize*sizeof(char));
     char c;