diff --git a/neuralNetworkTests.c b/neuralNetworkTests.c
index 21ab370..6cc4303 100644
--- a/neuralNetworkTests.c
+++ b/neuralNetworkTests.c
@@ -8,7 +8,32 @@
 
 static void prepareNeuralNetworkFile(const char *path, const NeuralNetwork nn)
 {
-    // TODO
+    FILE *file = fopen(path, "wb");
+
+    if(file != NULL){
+        const char *fileTag = "__info2_neural_network_file_format__";
+        fwrite(fileTag, sizeof(fileTag[0]), strlen(fileTag), file);
+
+        int inputDimension = nn.layers[0].weights.cols;
+        fwrite(&inputDimension,sizeof(inputDimension), 1, file);
+        
+        for (int i = 0; i < nn.numberOfLayers; i++)
+        {
+            unsigned int outputDimension = nn.layers[i].weights.rows;
+            fwrite(&outputDimension, sizeof(outputDimension), 1, file);
+
+            unsigned int numWeights = nn.layers[i].weights.rows * nn.layers[i].weights.cols;
+            fwrite(nn.layers[i].weights.buffer, sizeof(MatrixType), numWeights, file);
+
+            unsigned int numBiases = nn.layers[i].biases.rows * nn.layers[i].biases.cols;
+            fwrite(nn.layers[i].biases.buffer, sizeof(MatrixType), 1, file);
+        }
+
+        unsigned int outputDimension = 0;
+        fwrite(&outputDimension, sizeof(outputDimension), 1, file);
+
+        fclose(file);
+    }
 }
 
 void test_loadModelReturnsCorrectNumberOfLayers(void)
diff --git a/runImageInputTests b/runImageInputTests
index 6ee9ae7..2b262f4 100755
Binary files a/runImageInputTests and b/runImageInputTests differ
diff --git a/runImageInputTests.dSYM/Contents/Resources/DWARF/runImageInputTests b/runImageInputTests.dSYM/Contents/Resources/DWARF/runImageInputTests
index 88955c8..5bb7947 100644
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diff --git a/runMatrixTests b/runMatrixTests
index 8f166d2..735df69 100755
Binary files a/runMatrixTests and b/runMatrixTests differ
diff --git a/runMatrixTests.dSYM/Contents/Resources/DWARF/runMatrixTests b/runMatrixTests.dSYM/Contents/Resources/DWARF/runMatrixTests
index d37b96a..1ecd83f 100644
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